FPTP distortion, by single election
For each cycle in the data, we compute how the seats were actually allocated under First-Past-the-Post versus how they would have been allocated proportionally (using D'Hondt as a proxy for any proportional method — see methodology). The seats reallocated column is the count of seats First-Past-the-Post moved from where a proportional system would have placed them. 1,479 cycles ranked by raw count (more seats moved = bigger story), share as the tiebreak. The higher either number, the more First-Past-the-Post distorted the cycle's vote into something else.
This is per-cycle, apples-to-apples: it describes a single election in isolation, with no by-thirds caveat. For council-control changes (the rare event where the largest party of the running composition actually flipped), see /councils/flips. For per-seat distortion (one councillor elected on a tiny share of valid ballots), see /councils/below-quota.
Click a council name for the full per-cycle visualisation including the per-party vote share vs seat share viz. Filter or search below.
Unfairly awarded seats
0.0%25.6%51.1%
One hex = one council. “Unfairly awarded” = the seat went to a different party than a proportional re-count of the same votes (D'Hondt) would have produced. 0% = FPTP and proportional agreed; higher = bigger gap. Multi-member wards inflate the count slightly (bloc-vote caveat — see methodology).
1,479 of 1,479 shown.
| Year | Council | Seats | Reallocated Number of seats First-Past-the-Post placed differently from a proportional allocation. 0 = perfectly proportional; higher = more distorted. | % of seats Reallocated / total seats this cycle. The headline distortion measure: how much of the council's representation FPTP moved. | Most over-represented (FPTP gain vs proportional) |
|---|---|---|---|---|---|
| 2021 | Buckinghamshire | 147 | 45 | 30.6% | Conservative Party · 47.5% of votes → 76.9% of seats (+29.4 pts gap) |
| 2026 | Sunderland | 75 | 29 | 38.7% | Reform UK · 41.3% of votes → 77.3% of seats (+36.0 pts gap) |
| 2026 | Wakefield | 63 | 28 | 44.4% | Reform UK · 44.4% of votes → 92.1% of seats (+47.6 pts gap) |
| 2025 | Kent | 81 | 28 | 34.6% | Reform UK · 37.0% of votes → 70.4% of seats (+33.4 pts gap) |
| 2017 | Kent | 81 | 27 | 33.3% | Conservative Party · 49.5% of votes → 82.7% of seats (+33.2 pts gap) |
| 2025 | Durham | 98 | 27 | 27.6% | Reform UK · 40.8% of votes → 66.3% of seats (+25.5 pts gap) |
| 2026 | Sutton | 55 | 26 | 47.3% | Liberal Democrats · 44.4% of votes → 92.7% of seats (+48.3 pts gap) |
| 2026 | Ealing | 70 | 26 | 37.1% | Labour Party · 30.0% of votes → 65.7% of seats (+35.7 pts gap) |
| 2025 | Lancashire | 83 | 26 | 31.3% | Reform UK · 35.6% of votes → 62.7% of seats (+27.0 pts gap) |
| 2017 | Surrey | 81 | 25 | 30.9% | Conservative Party · 48.4% of votes → 75.3% of seats (+27.0 pts gap) |
| 2026 | West Surrey | 90 | 25 | 27.8% | Liberal Democrats · 35.7% of votes → 62.2% of seats (+26.5 pts gap) |
| 2018 | Manchester | 96 | 25 | 26.0% | Labour Party · 70.2% of votes → 97.9% of seats (+27.8 pts gap) |
| 2026 | Richmond upon Thames | 51 | 24 | 47.1% | Liberal Democrats · 51.2% of votes → 100.0% of seats (+48.8 pts gap) |
| 2022 | Lewisham | 54 | 24 | 44.4% | Labour Party · 55.3% of votes → 100.0% of seats (+44.7 pts gap) |
| 2026 | Sefton | 66 | 24 | 36.4% | Labour Party · 29.8% of votes → 54.5% of seats (+24.7 pts gap) |
| 2026 | Essex | 77 | 24 | 31.2% | Reform UK · 37.4% of votes → 68.8% of seats (+31.4 pts gap) |
| 2026 | South Cambridgeshire | 45 | 23 | 51.1% | Liberal Democrats · 42.7% of votes → 95.6% of seats (+52.9 pts gap) |
| 2025 | Staffordshire | 62 | 23 | 37.1% | Reform UK · 41.3% of votes → 79.0% of seats (+37.7 pts gap) |
| 2022 | Lambeth | 63 | 23 | 36.5% | Labour Party · 54.2% of votes → 92.1% of seats (+37.9 pts gap) |
| 2025 | Buckinghamshire | 97 | 23 | 23.7% | Conservative Party · 31.4% of votes → 49.5% of seats (+18.1 pts gap) |
| 2026 | Havering | 55 | 22 | 40.0% | Reform UK · 37.8% of votes → 70.9% of seats (+33.1 pts gap) |
| 2022 | Newham | 66 | 22 | 33.3% | Labour Party · 61.6% of votes → 97.0% of seats (+35.4 pts gap) |
| 2022 | Ealing | 70 | 22 | 31.4% | Labour Party · 51.1% of votes → 84.3% of seats (+33.1 pts gap) |
| 2021 | Kent | 81 | 22 | 27.2% | Conservative Party · 49.0% of votes → 76.5% of seats (+27.5 pts gap) |
| 2017 | Durham | 126 | 22 | 17.5% | Labour Party · 42.7% of votes → 58.7% of seats (+16.1 pts gap) |
| 2026 | Kingston upon Thames | 48 | 21 | 43.8% | Liberal Democrats · 44.9% of votes → 91.7% of seats (+46.7 pts gap) |
| 2026 | Barnet | 63 | 21 | 33.3% | Labour Party · 27.5% of votes → 49.2% of seats (+21.7 pts gap) |
| 2026 | Redbridge | 63 | 21 | 33.3% | Labour Party · 32.4% of votes → 68.3% of seats (+35.8 pts gap) |
| 2018 | Lambeth | 63 | 21 | 33.3% | Labour Party · 54.4% of votes → 90.5% of seats (+36.0 pts gap) |
| 2018 | Tower Hamlets | 45 | 20 | 44.4% | Labour Party · 46.1% of votes → 93.3% of seats (+47.2 pts gap) |
| 2022 | Kingston upon Thames | 48 | 20 | 41.7% | Liberal Democrats · 47.6% of votes → 91.7% of seats (+44.0 pts gap) |
| 2018 | Lewisham | 54 | 20 | 37.0% | Labour Party · 60.2% of votes → 100.0% of seats (+39.8 pts gap) |
| 2026 | Walsall | 60 | 20 | 33.3% | Reform UK · 37.3% of votes → 66.7% of seats (+29.3 pts gap) |
| 2018 | Bromley | 60 | 20 | 33.3% | Conservative Party · 50.3% of votes → 83.3% of seats (+33.1 pts gap) |
| 2021 | Staffordshire | 62 | 20 | 32.3% | Conservative Party · 56.6% of votes → 91.9% of seats (+35.4 pts gap) |
| 2022 | Redbridge | 63 | 20 | 31.7% | Labour Party · 58.4% of votes → 92.1% of seats (+33.7 pts gap) |
| 2018 | Brent | 63 | 20 | 31.7% | Labour Party · 61.4% of votes → 95.2% of seats (+33.8 pts gap) |
| 2026 | Croydon | 70 | 20 | 28.6% | Labour Party · 26.3% of votes → 42.9% of seats (+16.6 pts gap) |
| 2026 | East Surrey | 72 | 20 | 27.8% | Liberal Democrats · 29.4% of votes → 55.6% of seats (+26.2 pts gap) |
| 2017 | Essex | 75 | 20 | 26.7% | Conservative Party · 49.2% of votes → 74.7% of seats (+25.4 pts gap) |
| 2026 | St Helens | 46 | 19 | 41.3% | Reform UK · 39.7% of votes → 73.9% of seats (+34.2 pts gap) |
| 2026 | Thurrock | 49 | 19 | 38.8% | Reform UK · 51.5% of votes → 91.8% of seats (+40.4 pts gap) |
| 2022 | Islington | 51 | 19 | 37.3% | Labour Party · 54.7% of votes → 94.1% of seats (+39.5 pts gap) |
| 2026 | South Tyneside | 54 | 19 | 35.2% | Reform UK · 39.9% of votes → 75.9% of seats (+36.0 pts gap) |
| 2022 | Greenwich | 55 | 19 | 34.5% | Labour Party · 57.9% of votes → 94.5% of seats (+36.6 pts gap) |
| 2026 | Wandsworth | 58 | 19 | 32.8% | Conservative Party · 31.2% of votes → 50.0% of seats (+18.8 pts gap) |
| 2026 | Enfield | 63 | 19 | 30.2% | Labour Party · 24.2% of votes → 42.9% of seats (+18.6 pts gap) |
| 2025 | Nottinghamshire | 66 | 19 | 28.8% | Reform UK · 37.1% of votes → 63.6% of seats (+26.5 pts gap) |
| 2019 | East Riding | 67 | 19 | 28.4% | Conservative Party · 44.3% of votes → 73.1% of seats (+28.8 pts gap) |
| 2026 | Suffolk | 70 | 19 | 27.1% | Reform UK · 32.9% of votes → 58.6% of seats (+25.7 pts gap) |
| 2017 | Lincolnshire | 70 | 19 | 27.1% | Conservative Party · 53.5% of votes → 82.9% of seats (+29.4 pts gap) |
| 2017 | North Yorkshire | 70 | 19 | 27.1% | Conservative Party · 52.7% of votes → 75.7% of seats (+23.0 pts gap) |
| 2017 | West Sussex | 70 | 19 | 27.1% | Conservative Party · 51.3% of votes → 80.0% of seats (+28.7 pts gap) |
| 2021 | Suffolk | 75 | 19 | 25.3% | Conservative Party · 48.0% of votes → 73.3% of seats (+25.3 pts gap) |
| 2026 | Norfolk | 84 | 19 | 22.6% | Reform UK · 31.2% of votes → 47.6% of seats (+16.4 pts gap) |
| 2016 | Sheffield | 84 | 19 | 22.6% | Labour Party · 44.0% of votes → 67.9% of seats (+23.8 pts gap) |
| 2026 | Tower Hamlets | 45 | 18 | 40.0% | Aspire · 32.3% of votes → 73.3% of seats (+41.1 pts gap) |
| 2026 | Barking and Dagenham | 51 | 18 | 35.3% | Labour Party · 37.8% of votes → 74.5% of seats (+36.8 pts gap) |
| 2022 | Richmond upon Thames | 51 | 18 | 35.3% | Liberal Democrats · 55.5% of votes → 88.2% of seats (+32.7 pts gap) |
| 2026 | Westminster | 54 | 18 | 33.3% | Conservative Party · 35.1% of votes → 59.3% of seats (+24.2 pts gap) |
| 2022 | St Albans | 56 | 18 | 32.1% | Liberal Democrats · 57.2% of votes → 89.3% of seats (+32.0 pts gap) |
| 2026 | Merton | 57 | 18 | 31.6% | Labour Party · 30.8% of votes → 56.1% of seats (+25.3 pts gap) |
| 2018 | Hounslow | 60 | 18 | 30.0% | Labour Party · 54.1% of votes → 85.0% of seats (+30.9 pts gap) |
| 2025 | Oxfordshire | 69 | 18 | 26.1% | Liberal Democrats · 30.1% of votes → 52.2% of seats (+22.1 pts gap) |
| 2026 | Sandwell | 72 | 18 | 25.0% | Reform UK · 36.3% of votes → 56.9% of seats (+20.7 pts gap) |
| 2017 | Suffolk | 75 | 18 | 24.0% | Conservative Party · 45.7% of votes → 69.3% of seats (+23.7 pts gap) |
| 2021 | North Northamptonshire | 78 | 18 | 23.1% | Conservative Party · 52.6% of votes → 76.9% of seats (+24.3 pts gap) |
| 2021 | West Northamptonshire | 93 | 18 | 19.4% | Conservative Party · 50.8% of votes → 71.0% of seats (+20.2 pts gap) |
| 2018 | Islington | 48 | 17 | 35.4% | Labour Party · 60.6% of votes → 97.9% of seats (+37.3 pts gap) |
| 2026 | Hammersmith and Fulham | 50 | 17 | 34.0% | Labour Party · 40.7% of votes → 76.0% of seats (+35.3 pts gap) |
| 2019 | Leicester | 54 | 17 | 31.5% | Labour Party · 64.5% of votes → 98.1% of seats (+33.6 pts gap) |
| 2026 | Greenwich | 55 | 17 | 30.9% | Labour Party · 32.6% of votes → 63.6% of seats (+31.0 pts gap) |
| 2019 | East Suffolk | 55 | 17 | 30.9% | Conservative Party · 38.2% of votes → 70.9% of seats (+32.7 pts gap) |
| 2023 | Bath & North East Somerset | 59 | 17 | 28.8% | Liberal Democrats · 41.8% of votes → 69.5% of seats (+27.7 pts gap) |
| 2019 | Central Bedfordshire | 59 | 17 | 28.8% | Conservative Party · 43.3% of votes → 69.5% of seats (+26.2 pts gap) |
| 2021 | Salford | 60 | 17 | 28.3% | Labour Party · 57.4% of votes → 86.7% of seats (+29.3 pts gap) |
| 2022 | Hounslow | 62 | 17 | 27.4% | Labour Party · 54.3% of votes → 83.9% of seats (+29.5 pts gap) |
| 2017 | Staffordshire | 62 | 17 | 27.4% | Conservative Party · 53.8% of votes → 82.3% of seats (+28.5 pts gap) |
| 2025 | Derbyshire | 64 | 17 | 26.6% | Reform UK · 36.8% of votes → 65.6% of seats (+28.9 pts gap) |
| 2018 | Ealing | 69 | 17 | 24.6% | Labour Party · 56.2% of votes → 82.6% of seats (+26.4 pts gap) |
| 2025 | West Northamptonshire | 76 | 17 | 22.4% | Reform UK · 33.0% of votes → 55.3% of seats (+22.3 pts gap) |
| 2018 | Newcastle upon Tyne | 78 | 17 | 21.8% | Labour Party · 48.4% of votes → 71.8% of seats (+23.4 pts gap) |
| 2022 | Cardiff | 79 | 17 | 21.5% | Labour Party · 47.5% of votes → 69.6% of seats (+22.2 pts gap) |
| 2025 | Wiltshire | 98 | 17 | 17.3% | Liberal Democrats · 33.9% of votes → 43.9% of seats (+9.9 pts gap) |
| 2023 | Nottingham | 55 | 16 | 29.1% | Labour Party · 61.7% of votes → 92.7% of seats (+31.0 pts gap) |
| 2026 | Hackney | 57 | 16 | 28.1% | Green Party · 43.1% of votes → 73.7% of seats (+30.6 pts gap) |
| 2022 | Haringey | 57 | 16 | 28.1% | Labour Party · 59.8% of votes → 87.7% of seats (+28.0 pts gap) |
| 2021 | Worcestershire | 57 | 16 | 28.1% | Conservative Party · 49.6% of votes → 78.9% of seats (+29.3 pts gap) |
| 2024 | Warrington | 58 | 16 | 27.6% | Labour Party · 47.3% of votes → 72.4% of seats (+25.1 pts gap) |
| 2026 | Barnsley | 63 | 16 | 25.4% | Reform UK · 42.0% of votes → 66.7% of seats (+24.6 pts gap) |
| 2025 | North Northamptonshire | 68 | 16 | 23.5% | Reform UK · 35.0% of votes → 58.8% of seats (+23.8 pts gap) |
| 2017 | Caerphilly | 72 | 16 | 22.2% | Labour Party · 43.1% of votes → 68.1% of seats (+24.9 pts gap) |
| 2025 | Shropshire | 74 | 16 | 21.6% | Liberal Democrats · 34.2% of votes → 56.8% of seats (+22.6 pts gap) |
| 2021 | Essex | 75 | 16 | 21.3% | Conservative Party · 48.7% of votes → 69.3% of seats (+20.7 pts gap) |
| 2021 | Hampshire | 78 | 16 | 20.5% | Conservative Party · 50.6% of votes → 71.8% of seats (+21.2 pts gap) |
| 2021 | Surrey | 81 | 16 | 19.8% | Conservative Party · 42.2% of votes → 58.0% of seats (+15.8 pts gap) |
| 2021 | Norfolk | 84 | 16 | 19.0% | Conservative Party · 48.4% of votes → 69.0% of seats (+20.6 pts gap) |
| 2021 | Cornwall | 87 | 16 | 18.4% | Conservative Party · 37.3% of votes → 54.0% of seats (+16.8 pts gap) |
| 2024 | Cheltenham | 40 | 15 | 37.5% | Liberal Democrats · 51.9% of votes → 90.0% of seats (+38.1 pts gap) |
| 2019 | East Hertfordshire | 48 | 15 | 31.3% | Conservative Party · 45.7% of votes → 79.2% of seats (+33.4 pts gap) |
| 2017 | Buckinghamshire | 49 | 15 | 30.6% | Conservative Party · 53.1% of votes → 83.7% of seats (+30.6 pts gap) |
| 2026 | Harrow | 53 | 15 | 28.3% | Conservative Party · 47.0% of votes → 77.4% of seats (+30.4 pts gap) |
| 2026 | Lewisham | 54 | 15 | 27.8% | Green Party · 43.6% of votes → 74.1% of seats (+30.4 pts gap) |
| 2018 | Camden | 54 | 15 | 27.8% | Labour Party · 50.1% of votes → 79.6% of seats (+29.5 pts gap) |
| 2018 | Richmond upon Thames | 54 | 15 | 27.8% | Liberal Democrats · 46.7% of votes → 72.2% of seats (+25.5 pts gap) |
| 2022 | Camden | 55 | 15 | 27.3% | Labour Party · 55.8% of votes → 85.5% of seats (+29.6 pts gap) |
| 2019 | Nottingham | 55 | 15 | 27.3% | Labour Party · 62.0% of votes → 90.9% of seats (+28.9 pts gap) |
| 2023 | Tameside | 57 | 15 | 26.3% | Labour Party · 63.3% of votes → 91.2% of seats (+28.0 pts gap) |
| 2022 | Brent | 57 | 15 | 26.3% | Labour Party · 57.6% of votes → 86.0% of seats (+28.4 pts gap) |
| 2022 | Hackney | 57 | 15 | 26.3% | Labour Party · 58.9% of votes → 87.7% of seats (+28.8 pts gap) |
| 2018 | Hackney | 57 | 15 | 26.3% | Labour Party · 63.0% of votes → 91.2% of seats (+28.3 pts gap) |
| 2026 | Bromley | 58 | 15 | 25.9% | Conservative Party · 36.2% of votes → 60.3% of seats (+24.1 pts gap) |
| 2022 | Bromley | 58 | 15 | 25.9% | Conservative Party · 41.6% of votes → 62.1% of seats (+20.5 pts gap) |
| 2016 | Warrington | 58 | 15 | 25.9% | Labour Party · 48.8% of votes → 77.6% of seats (+28.8 pts gap) |
| 2025 | Cambridgeshire | 61 | 15 | 24.6% | Liberal Democrats · 27.4% of votes → 50.8% of seats (+23.4 pts gap) |
| 2022 | Southwark | 63 | 15 | 23.8% | Labour Party · 56.4% of votes → 82.5% of seats (+26.2 pts gap) |
| 2026 | Kirklees | 69 | 15 | 21.7% | Reform UK · 30.0% of votes → 42.0% of seats (+12.1 pts gap) |
| 2025 | Lincolnshire | 70 | 15 | 21.4% | Reform UK · 39.4% of votes → 62.9% of seats (+23.4 pts gap) |
| 2022 | Croydon | 70 | 15 | 21.4% | Labour Party · 34.4% of votes → 48.6% of seats (+14.2 pts gap) |
| 2021 | West Sussex | 70 | 15 | 21.4% | Conservative Party · 46.8% of votes → 68.6% of seats (+21.8 pts gap) |
| 2023 | Wigan | 75 | 15 | 20.0% | Labour Party · 60.9% of votes → 85.3% of seats (+24.4 pts gap) |
| 2019 | Bournemouth, Christchurch and Poole | 76 | 15 | 19.7% | Conservative Party · 32.1% of votes → 47.4% of seats (+15.2 pts gap) |
| 2026 | Newcastle upon Tyne | 78 | 15 | 19.2% | Liberal Democrats · 23.1% of votes → 32.1% of seats (+8.9 pts gap) |
| 2021 | Hertfordshire | 78 | 15 | 19.2% | Conservative Party · 43.3% of votes → 59.0% of seats (+15.6 pts gap) |
| 2019 | Dorset | 82 | 15 | 18.3% | Conservative Party · 39.3% of votes → 52.4% of seats (+13.1 pts gap) |
| 2023 | Liverpool | 85 | 15 | 17.6% | Labour Party · 53.1% of votes → 71.8% of seats (+18.6 pts gap) |
| 2017 | Wiltshire | 97 | 15 | 15.5% | Conservative Party · 52.1% of votes → 69.1% of seats (+16.9 pts gap) |
| 2018 | Leeds | 99 | 15 | 15.2% | Labour Party · 46.3% of votes → 61.6% of seats (+15.3 pts gap) |
| 2016 | Cherwell | 48 | 14 | 29.2% | Conservative Party · 49.1% of votes → 79.2% of seats (+30.0 pts gap) |
| 2023 | Southampton | 51 | 14 | 27.5% | Labour Party · 45.2% of votes → 74.5% of seats (+29.4 pts gap) |
| 2026 | Calderdale | 54 | 14 | 25.9% | Reform UK · 36.2% of votes → 63.0% of seats (+26.7 pts gap) |
| 2018 | Sutton | 54 | 14 | 25.9% | Liberal Democrats · 38.8% of votes → 61.1% of seats (+22.3 pts gap) |
| 2021 | Doncaster | 55 | 14 | 25.5% | Labour Party · 46.5% of votes → 72.7% of seats (+26.2 pts gap) |
| 2017 | Doncaster | 55 | 14 | 25.5% | Labour Party · 50.7% of votes → 78.2% of seats (+27.5 pts gap) |
| 2021 | Warwickshire | 57 | 14 | 24.6% | Conservative Party · 48.6% of votes → 73.7% of seats (+25.1 pts gap) |
| 2026 | Milton Keynes | 60 | 14 | 23.3% | Liberal Democrats · 18.5% of votes → 33.3% of seats (+14.8 pts gap) |
| 2024 | North Tyneside | 60 | 14 | 23.3% | Labour Party · 58.0% of votes → 85.0% of seats (+27.0 pts gap) |
| 2017 | Devon | 60 | 14 | 23.3% | Conservative Party · 44.5% of votes → 70.0% of seats (+25.5 pts gap) |
| 2016 | Rotherham | 63 | 14 | 22.2% | Labour Party · 51.3% of votes → 76.2% of seats (+24.9 pts gap) |
| 2021 | Derbyshire | 64 | 14 | 21.9% | Conservative Party · 47.7% of votes → 70.3% of seats (+22.6 pts gap) |
| 2021 | Nottinghamshire | 66 | 14 | 21.2% | Conservative Party · 42.4% of votes → 56.1% of seats (+13.6 pts gap) |
| 2021 | Lincolnshire | 70 | 14 | 20.0% | Conservative Party · 55.4% of votes → 77.1% of seats (+21.7 pts gap) |
| 2022 | Rhondda Cynon Taf | 75 | 14 | 18.7% | Labour Party · 58.2% of votes → 78.7% of seats (+20.4 pts gap) |
| 2026 | Hampshire | 78 | 14 | 17.9% | Liberal Democrats · 25.4% of votes → 33.3% of seats (+7.9 pts gap) |
| 2017 | Hampshire | 78 | 14 | 17.9% | Conservative Party · 52.2% of votes → 71.8% of seats (+19.6 pts gap) |
| 2017 | Hertfordshire | 78 | 14 | 17.9% | Conservative Party · 46.0% of votes → 65.4% of seats (+19.4 pts gap) |
| 2017 | Norfolk | 84 | 14 | 16.7% | Conservative Party · 48.8% of votes → 65.5% of seats (+16.7 pts gap) |
| 2021 | Wiltshire | 98 | 14 | 14.3% | Conservative Party · 47.3% of votes → 62.2% of seats (+14.9 pts gap) |
| 2021 | County Durham | 126 | 14 | 11.1% | Labour Party · 37.2% of votes → 42.1% of seats (+4.9 pts gap) |
| 2023 | Ashfield | 35 | 13 | 37.1% | Ashfield Independents · 51.6% of votes → 91.4% of seats (+39.8 pts gap) |
| 2024 | Castle Point | 39 | 13 | 33.3% | Canvey Island Independent Party · 20.4% of votes → 38.5% of seats (+18.1 pts gap) |
| 2023 | Mid Devon | 42 | 13 | 31.0% | Liberal Democrats · 46.9% of votes → 78.6% of seats (+31.7 pts gap) |
| 2019 | Bracknell Forest | 42 | 13 | 31.0% | Conservative Party · 56.7% of votes → 90.5% of seats (+33.7 pts gap) |
| 2022 | South Cambridgeshire | 45 | 13 | 28.9% | Liberal Democrats · 52.1% of votes → 82.2% of seats (+30.2 pts gap) |
| 2018 | Kingston upon Thames | 48 | 13 | 27.1% | Liberal Democrats · 51.7% of votes → 81.3% of seats (+29.6 pts gap) |
| 2019 | Braintree | 49 | 13 | 26.5% | Conservative Party · 45.5% of votes → 69.4% of seats (+23.9 pts gap) |
| 2019 | Sevenoaks | 49 | 13 | 26.5% | Conservative Party · 58.0% of votes → 83.7% of seats (+25.7 pts gap) |
| 2023 | Waverley | 50 | 13 | 26.0% | Liberal Democrats · 30.1% of votes → 44.0% of seats (+13.9 pts gap) |
| 2026 | Hillingdon | 51 | 13 | 25.5% | Conservative Party · 40.0% of votes → 58.8% of seats (+18.8 pts gap) |
| 2019 | Charnwood | 52 | 13 | 25.0% | Conservative Party · 44.7% of votes → 71.2% of seats (+26.4 pts gap) |
| 2026 | Camden | 55 | 13 | 23.6% | Labour Party · 32.8% of votes → 54.5% of seats (+21.7 pts gap) |
| 2025 | Doncaster | 55 | 13 | 23.6% | Reform UK · 40.6% of votes → 67.3% of seats (+26.7 pts gap) |
| 2017 | Northamptonshire | 57 | 13 | 22.8% | Conservative Party · 51.1% of votes → 75.4% of seats (+24.3 pts gap) |
| 2021 | Warrington | 58 | 13 | 22.4% | Labour Party · 38.9% of votes → 62.1% of seats (+23.1 pts gap) |
| 2019 | Bath and North East Somerset | 59 | 13 | 22.0% | Liberal Democrats · 43.7% of votes → 62.7% of seats (+19.1 pts gap) |
| 2026 | Waltham Forest | 60 | 13 | 21.7% | Green Party · 37.2% of votes → 51.7% of seats (+14.5 pts gap) |
| 2021 | Devon | 60 | 13 | 21.7% | Conservative Party · 42.8% of votes → 65.0% of seats (+22.2 pts gap) |
| 2018 | Newham | 60 | 13 | 21.7% | Labour Party · 74.4% of votes → 100.0% of seats (+25.6 pts gap) |
| 2018 | Westminster | 60 | 13 | 21.7% | Conservative Party · 44.8% of votes → 68.3% of seats (+23.5 pts gap) |
| 2016 | Peterborough | 60 | 13 | 21.7% | Conservative Party · 38.6% of votes → 51.7% of seats (+13.0 pts gap) |
| 2023 | Trafford | 63 | 13 | 20.6% | Labour Party · 44.2% of votes → 65.1% of seats (+20.9 pts gap) |
| 2018 | Redbridge | 63 | 13 | 20.6% | Labour Party · 58.4% of votes → 81.0% of seats (+22.6 pts gap) |
| 2018 | Southwark | 63 | 13 | 20.6% | Labour Party · 55.3% of votes → 77.8% of seats (+22.5 pts gap) |
| 2022 | Westmorland and Furness | 65 | 13 | 20.0% | Liberal Democrats · 39.1% of votes → 55.4% of seats (+16.3 pts gap) |
| 2026 | Gateshead | 66 | 13 | 19.7% | Reform UK · 37.0% of votes → 57.6% of seats (+20.5 pts gap) |
| 2022 | Caerphilly | 69 | 13 | 18.8% | Labour Party · 43.4% of votes → 63.8% of seats (+20.3 pts gap) |
| 2025 | Hertfordshire | 78 | 13 | 16.7% | Liberal Democrats · 26.0% of votes → 39.7% of seats (+13.8 pts gap) |
| 2026 | Bradford | 87 | 13 | 14.9% | Reform UK · 22.6% of votes → 33.3% of seats (+10.8 pts gap) |
| 2018 | Birmingham | 101 | 13 | 12.9% | Labour Party · 52.6% of votes → 66.3% of seats (+13.7 pts gap) |
| 2026 | Wigan | 25 | 12 | 48.0% | Reform UK · 46.3% of votes → 96.0% of seats (+49.7 pts gap) |
| 2023 | Bolsover | 37 | 12 | 32.4% | Labour Party · 48.8% of votes → 83.8% of seats (+35.0 pts gap) |
| 2023 | Vale Of White Horse | 38 | 12 | 31.6% | Liberal Democrats · 54.6% of votes → 89.5% of seats (+34.9 pts gap) |
| 2023 | Mole Valley | 39 | 12 | 30.8% | Liberal Democrats · 48.4% of votes → 76.9% of seats (+28.5 pts gap) |
| 2018 | Eastleigh | 39 | 12 | 30.8% | Liberal Democrats · 51.1% of votes → 82.1% of seats (+31.0 pts gap) |
| 2019 | Wealden | 44 | 12 | 27.3% | Conservative Party · 45.2% of votes → 75.0% of seats (+29.8 pts gap) |
| 2026 | Bexley | 45 | 12 | 26.7% | Conservative Party · 36.5% of votes → 64.4% of seats (+27.9 pts gap) |
| 2019 | Reigate and Banstead | 45 | 12 | 26.7% | Conservative Party · 41.6% of votes → 64.4% of seats (+22.8 pts gap) |
| 2018 | South Cambridgeshire | 45 | 12 | 26.7% | Liberal Democrats · 38.4% of votes → 66.7% of seats (+28.3 pts gap) |
| 2019 | South Norfolk | 46 | 12 | 26.1% | Conservative Party · 47.0% of votes → 76.1% of seats (+29.1 pts gap) |
| 2019 | Bassetlaw | 47 | 12 | 25.5% | Labour Party · 56.1% of votes → 78.7% of seats (+22.7 pts gap) |
| 2023 | Guildford | 48 | 12 | 25.0% | Liberal Democrats · 30.7% of votes → 52.1% of seats (+21.4 pts gap) |
| 2023 | Horsham | 48 | 12 | 25.0% | Liberal Democrats · 35.2% of votes → 58.3% of seats (+23.1 pts gap) |
| 2021 | Oxford | 48 | 12 | 25.0% | Labour Party · 44.9% of votes → 70.8% of seats (+25.9 pts gap) |
| 2026 | Kensington and Chelsea | 50 | 12 | 24.0% | Conservative Party · 50.4% of votes → 68.0% of seats (+17.6 pts gap) |
| 2026 | Islington | 51 | 12 | 23.5% | Labour Party · 38.5% of votes → 62.7% of seats (+24.2 pts gap) |
| 2019 | Dacorum | 51 | 12 | 23.5% | Conservative Party · 42.6% of votes → 60.8% of seats (+18.1 pts gap) |
| 2018 | Greenwich | 51 | 12 | 23.5% | Labour Party · 56.0% of votes → 82.4% of seats (+26.3 pts gap) |
| 2023 | Brighton & Hove | 54 | 12 | 22.2% | Labour Party · 47.1% of votes → 70.4% of seats (+23.2 pts gap) |
| 2025 | Gloucestershire | 55 | 12 | 21.8% | Liberal Democrats · 27.2% of votes → 49.1% of seats (+21.9 pts gap) |
| 2021 | Leicestershire | 55 | 12 | 21.8% | Conservative Party · 51.3% of votes → 76.4% of seats (+25.0 pts gap) |
| 2017 | Worcestershire | 57 | 12 | 21.1% | Conservative Party · 46.8% of votes → 70.2% of seats (+23.3 pts gap) |
| 2023 | Wolverhampton | 60 | 12 | 20.0% | Labour Party · 57.1% of votes → 78.3% of seats (+21.3 pts gap) |
| 2019 | South Somerset | 60 | 12 | 20.0% | Liberal Democrats · 47.9% of votes → 68.3% of seats (+20.5 pts gap) |
| 2017 | Cambridgeshire | 61 | 12 | 19.7% | Conservative Party · 40.7% of votes → 59.0% of seats (+18.3 pts gap) |
| 2023 | Stockport | 63 | 12 | 19.0% | Liberal Democrats · 38.4% of votes → 47.6% of seats (+9.2 pts gap) |
| 2026 | Newham | 66 | 12 | 18.2% | Labour Party · 29.0% of votes → 39.4% of seats (+10.4 pts gap) |
| 2023 | East Riding Of Yorkshire | 67 | 12 | 17.9% | Conservative Party · 35.7% of votes → 43.3% of seats (+7.5 pts gap) |
| 2017 | Swansea | 72 | 12 | 16.7% | Labour Party · 50.2% of votes → 66.7% of seats (+16.5 pts gap) |
| 2017 | Shropshire | 73 | 12 | 16.4% | Conservative Party · 48.8% of votes → 65.8% of seats (+17.0 pts gap) |
| 2017 | Rhondda Cynon Taf | 75 | 12 | 16.0% | Labour Party · 46.0% of votes → 62.7% of seats (+16.7 pts gap) |
| 2024 | Dorset | 82 | 12 | 14.6% | Liberal Democrats · 37.3% of votes → 51.2% of seats (+13.9 pts gap) |
| 2021 | Lancashire | 84 | 12 | 14.3% | Conservative Party · 43.9% of votes → 57.1% of seats (+13.2 pts gap) |
| 2022 | Birmingham | 101 | 12 | 11.9% | Labour Party · 51.5% of votes → 64.4% of seats (+12.8 pts gap) |
| 2022 | Somerset | 110 | 12 | 10.9% | Liberal Democrats · 43.6% of votes → 55.5% of seats (+11.8 pts gap) |
| 2026 | Dudley | 25 | 11 | 44.0% | Reform UK · 41.9% of votes → 88.0% of seats (+46.1 pts gap) |
| 2024 | Manchester | 33 | 11 | 33.3% | Labour Party · 54.7% of votes → 90.9% of seats (+36.3 pts gap) |
| 2019 | Manchester | 33 | 11 | 33.3% | Labour Party · 58.5% of votes → 97.0% of seats (+38.4 pts gap) |
| 2019 | Norwich | 39 | 11 | 28.2% | Labour Party · 40.5% of votes → 69.2% of seats (+28.7 pts gap) |
| 2016 | Exeter | 39 | 11 | 28.2% | Labour Party · 47.5% of votes → 76.9% of seats (+29.4 pts gap) |
| 2019 | North Norfolk | 40 | 11 | 27.5% | Liberal Democrats · 50.1% of votes → 75.0% of seats (+24.9 pts gap) |
| 2024 | Basildon | 42 | 11 | 26.2% | Labour Party · 25.5% of votes → 42.9% of seats (+17.4 pts gap) |
| 2023 | Amber Valley | 42 | 11 | 26.2% | Labour Party · 34.5% of votes → 61.9% of seats (+27.4 pts gap) |
| 2021 | Cambridge | 42 | 11 | 26.2% | Labour Party · 40.7% of votes → 64.3% of seats (+23.6 pts gap) |
| 2024 | Tandridge | 43 | 11 | 25.6% | Liberal Democrats · 16.4% of votes → 25.6% of seats (+9.2 pts gap) |
| 2026 | Newcastle-under-Lyme | 44 | 11 | 25.0% | Reform UK · 41.1% of votes → 61.4% of seats (+20.3 pts gap) |
| 2022 | Cumberland | 46 | 11 | 23.9% | Labour Party · 39.1% of votes → 65.2% of seats (+26.1 pts gap) |
| 2019 | Broadland | 47 | 11 | 23.4% | Conservative Party · 45.8% of votes → 70.2% of seats (+24.4 pts gap) |
| 2023 | Bassetlaw | 48 | 11 | 22.9% | Labour Party · 54.6% of votes → 79.2% of seats (+24.6 pts gap) |
| 2022 | Hammersmith and Fulham | 50 | 11 | 22.0% | Labour Party · 57.1% of votes → 80.0% of seats (+22.9 pts gap) |
| 2022 | Newport | 51 | 11 | 21.6% | Labour Party · 49.1% of votes → 68.6% of seats (+19.6 pts gap) |
| 2018 | Barking and Dagenham | 51 | 11 | 21.6% | Labour Party · 76.6% of votes → 100.0% of seats (+23.4 pts gap) |
| 2019 | Tonbridge and Malling | 52 | 11 | 21.2% | Conservative Party · 46.9% of votes → 71.2% of seats (+24.3 pts gap) |
| 2026 | Coventry | 54 | 11 | 20.4% | Labour Party · 29.3% of votes → 44.4% of seats (+15.1 pts gap) |
| 2021 | Halton | 54 | 11 | 20.4% | Labour Party · 64.3% of votes → 88.9% of seats (+24.6 pts gap) |
| 2018 | Havering | 54 | 11 | 20.4% | Conservative Party · 37.1% of votes → 46.3% of seats (+9.2 pts gap) |
| 2019 | Medway | 55 | 11 | 20.0% | Conservative Party · 40.0% of votes → 60.0% of seats (+20.0 pts gap) |
| 2026 | Brent | 57 | 11 | 19.3% | Labour Party · 29.8% of votes → 45.6% of seats (+15.9 pts gap) |
| 2022 | Merton | 57 | 11 | 19.3% | Labour Party · 41.9% of votes → 54.4% of seats (+12.4 pts gap) |
| 2019 | Somerset West and Taunton | 58 | 11 | 19.0% | Liberal Democrats · 40.6% of votes → 51.7% of seats (+11.2 pts gap) |
| 2026 | Hounslow | 62 | 11 | 17.7% | Labour Party · 32.6% of votes → 51.6% of seats (+19.0 pts gap) |
| 2022 | Barnet | 63 | 11 | 17.5% | Labour Party · 46.7% of votes → 65.1% of seats (+18.4 pts gap) |
| 2026 | West Sussex | 70 | 11 | 15.7% | Liberal Democrats · 22.8% of votes → 32.9% of seats (+10.1 pts gap) |
| 2023 | Cheshire East | 82 | 11 | 13.4% | Labour Party · 30.2% of votes → 37.8% of seats (+7.7 pts gap) |
| 2025 | Cornwall | 87 | 11 | 12.6% | Liberal Democrats · 24.4% of votes → 29.9% of seats (+5.4 pts gap) |
| 2023 | Leeds | 33 | 10 | 30.3% | Labour Party · 44.6% of votes → 66.7% of seats (+22.1 pts gap) |
| 2021 | Manchester | 34 | 10 | 29.4% | Labour Party · 65.5% of votes → 97.1% of seats (+31.6 pts gap) |
| 2023 | Epsom & Ewell | 35 | 10 | 28.6% | RES · 41.2% of votes → 68.6% of seats (+27.4 pts gap) |
| 2023 | South Oxfordshire | 36 | 10 | 27.8% | Liberal Democrats · 35.9% of votes → 58.3% of seats (+22.4 pts gap) |
| 2024 | Stevenage | 39 | 10 | 25.6% | Labour Party · 51.7% of votes → 79.5% of seats (+27.8 pts gap) |
| 2019 | Uttlesford | 39 | 10 | 25.6% | R4U · 41.0% of votes → 66.7% of seats (+25.6 pts gap) |
| 2018 | Harrogate | 40 | 10 | 25.0% | Conservative Party · 53.6% of votes → 77.5% of seats (+23.9 pts gap) |
| 2019 | Gedling | 41 | 10 | 24.4% | Labour Party · 47.8% of votes → 70.7% of seats (+22.9 pts gap) |
| 2023 | Fenland | 43 | 10 | 23.3% | Conservative Party · 56.9% of votes → 81.4% of seats (+24.5 pts gap) |
| 2018 | Hammersmith and Fulham | 46 | 10 | 21.7% | Labour Party · 54.3% of votes → 76.1% of seats (+21.8 pts gap) |
| 2019 | Mendip | 47 | 10 | 21.3% | Liberal Democrats · 33.9% of votes → 46.8% of seats (+12.9 pts gap) |
| 2023 | Braintree | 49 | 10 | 20.4% | Conservative Party · 39.8% of votes → 53.1% of seats (+13.3 pts gap) |
| 2022 | Kensington and Chelsea | 50 | 10 | 20.0% | Conservative Party · 48.6% of votes → 70.0% of seats (+21.4 pts gap) |
| 2018 | Kensington and Chelsea | 50 | 10 | 20.0% | Conservative Party · 51.6% of votes → 72.0% of seats (+20.4 pts gap) |
| 2017 | Newport | 50 | 10 | 20.0% | Labour Party · 42.2% of votes → 62.0% of seats (+19.8 pts gap) |
| 2024 | North Hertfordshire | 51 | 10 | 19.6% | Labour Party · 35.6% of votes → 49.0% of seats (+13.5 pts gap) |
| 2022 | Bury | 51 | 10 | 19.6% | Labour Party · 44.5% of votes → 56.9% of seats (+12.3 pts gap) |
| 2023 | Telford & Wrekin | 54 | 10 | 18.5% | Labour Party · 52.8% of votes → 70.4% of seats (+17.6 pts gap) |
| 2019 | South Kesteven | 54 | 10 | 18.5% | Conservative Party · 53.3% of votes → 70.4% of seats (+17.0 pts gap) |
| 2019 | Telford and Wrekin | 54 | 10 | 18.5% | Labour Party · 47.6% of votes → 66.7% of seats (+19.1 pts gap) |
| 2025 | Warwickshire | 57 | 10 | 17.5% | Reform UK · 30.6% of votes → 40.4% of seats (+9.7 pts gap) |
| 2019 | Chelmsford | 57 | 10 | 17.5% | Liberal Democrats · 39.9% of votes → 54.4% of seats (+14.5 pts gap) |
| 2018 | Haringey | 57 | 10 | 17.5% | Labour Party · 57.3% of votes → 73.7% of seats (+16.3 pts gap) |
| 2025 | Devon | 60 | 10 | 16.7% | Liberal Democrats · 28.3% of votes → 45.0% of seats (+16.7 pts gap) |
| 2022 | Waltham Forest | 60 | 10 | 16.7% | Labour Party · 59.1% of votes → 78.3% of seats (+19.2 pts gap) |
| 2022 | Rochdale | 60 | 10 | 16.7% | Labour Party · 49.9% of votes → 68.3% of seats (+18.4 pts gap) |
| 2018 | Waltham Forest | 60 | 10 | 16.7% | Labour Party · 58.1% of votes → 76.7% of seats (+18.5 pts gap) |
| 2023 | Central Bedfordshire | 63 | 10 | 15.9% | Independent · 29.5% of votes → 42.9% of seats (+13.4 pts gap) |
| 2022 | Enfield | 63 | 10 | 15.9% | Labour Party · 45.4% of votes → 60.3% of seats (+14.9 pts gap) |
| 2018 | Enfield | 63 | 10 | 15.9% | Labour Party · 54.8% of votes → 73.0% of seats (+18.2 pts gap) |
| 2017 | Nottinghamshire | 66 | 10 | 15.2% | Conservative Party · 38.1% of votes → 47.0% of seats (+8.9 pts gap) |
| 2025 | Northumberland | 69 | 10 | 14.5% | Conservative Party · 28.8% of votes → 37.7% of seats (+8.8 pts gap) |
| 2023 | Cheshire West & Chester | 70 | 10 | 14.3% | Labour Party · 42.6% of votes → 55.7% of seats (+13.2 pts gap) |
| 2016 | Bristol | 70 | 10 | 14.3% | Labour Party · 36.6% of votes → 52.9% of seats (+16.3 pts gap) |
| 2017 | Cardiff | 75 | 10 | 13.3% | Labour Party · 39.0% of votes → 53.3% of seats (+14.3 pts gap) |
| 2023 | Bournemouth, Christchurch & Poole | 76 | 10 | 13.2% | Liberal Democrats · 31.3% of votes → 36.8% of seats (+5.5 pts gap) |
| 2022 | North Yorkshire | 90 | 10 | 11.1% | Conservative Party · 41.2% of votes → 52.2% of seats (+11.0 pts gap) |
| 2026 | Tameside | 19 | 9 | 47.4% | Reform UK · 41.9% of votes → 94.7% of seats (+52.8 pts gap) |
| 2026 | St Albans | 22 | 9 | 40.9% | Liberal Democrats · 45.2% of votes → 86.4% of seats (+41.2 pts gap) |
| 2019 | Wigan | 25 | 9 | 36.0% | Labour Party · 41.4% of votes → 80.0% of seats (+38.6 pts gap) |
| 2016 | Manchester | 32 | 9 | 28.1% | Labour Party · 64.1% of votes → 96.9% of seats (+32.7 pts gap) |
| 2016 | Lincoln | 33 | 9 | 27.3% | Labour Party · 50.2% of votes → 81.8% of seats (+31.6 pts gap) |
| 2023 | Chichester | 36 | 9 | 25.0% | Liberal Democrats · 50.9% of votes → 69.4% of seats (+18.5 pts gap) |
| 2023 | Mansfield | 36 | 9 | 25.0% | Labour Party · 43.2% of votes → 69.4% of seats (+26.2 pts gap) |
| 2016 | Watford | 36 | 9 | 25.0% | Liberal Democrats · 42.2% of votes → 69.4% of seats (+27.3 pts gap) |
| 2019 | Vale of White Horse | 37 | 9 | 24.3% | Liberal Democrats · 58.3% of votes → 83.8% of seats (+25.4 pts gap) |
| 2019 | Wychavon | 37 | 9 | 24.3% | Conservative Party · 53.5% of votes → 78.4% of seats (+24.8 pts gap) |
| 2019 | Epsom and Ewell | 38 | 9 | 23.7% | RAEE · 39.6% of votes → 55.3% of seats (+15.7 pts gap) |
| 2019 | Ribble Valley | 38 | 9 | 23.7% | Conservative Party · 53.1% of votes → 68.4% of seats (+15.3 pts gap) |
| 2026 | Isle of Wight | 39 | 9 | 23.1% | Reform UK · 31.9% of votes → 48.7% of seats (+16.8 pts gap) |
| 2019 | Canterbury | 39 | 9 | 23.1% | Conservative Party · 35.4% of votes → 59.0% of seats (+23.6 pts gap) |
| 2023 | North Norfolk | 40 | 9 | 22.5% | Liberal Democrats · 43.9% of votes → 62.5% of seats (+18.6 pts gap) |
| 2023 | Bracknell Forest | 41 | 9 | 22.0% | Labour Party · 32.2% of votes → 53.7% of seats (+21.4 pts gap) |
| 2023 | Lewes | 41 | 9 | 22.0% | Green Party · 31.6% of votes → 41.5% of seats (+9.9 pts gap) |
| 2023 | South Staffordshire | 42 | 9 | 21.4% | Conservative Party · 47.0% of votes → 69.0% of seats (+22.0 pts gap) |
| 2023 | High Peak | 43 | 9 | 20.9% | Labour Party · 48.3% of votes → 69.8% of seats (+21.4 pts gap) |
| 2023 | Wealden | 44 | 9 | 20.5% | Liberal Democrats · 18.5% of votes → 29.5% of seats (+11.0 pts gap) |
| 2022 | Bexley | 45 | 9 | 20.0% | Conservative Party · 50.8% of votes → 73.3% of seats (+22.6 pts gap) |
| 2022 | Denbighshire | 47 | 9 | 19.1% | Labour Party · 25.1% of votes → 40.4% of seats (+15.3 pts gap) |
| 2019 | Teignbridge | 47 | 9 | 19.1% | Liberal Democrats · 40.6% of votes → 55.3% of seats (+14.7 pts gap) |
| 2019 | York | 47 | 9 | 19.1% | Liberal Democrats · 34.5% of votes → 44.7% of seats (+10.2 pts gap) |
| 2019 | Guildford | 48 | 9 | 18.8% | RGV · 22.9% of votes → 31.3% of seats (+8.3 pts gap) |
| 2019 | Horsham | 48 | 9 | 18.8% | Conservative Party · 48.5% of votes → 66.7% of seats (+18.2 pts gap) |
| 2026 | East Sussex | 50 | 9 | 18.0% | Reform UK · 29.4% of votes → 44.0% of seats (+14.6 pts gap) |
| 2019 | Mid Sussex | 50 | 9 | 18.0% | Conservative Party · 40.0% of votes → 60.0% of seats (+20.0 pts gap) |
| 2019 | Wyre | 50 | 9 | 18.0% | Conservative Party · 59.6% of votes → 74.0% of seats (+14.4 pts gap) |
| 2017 | East Sussex | 50 | 9 | 18.0% | Conservative Party · 45.6% of votes → 60.0% of seats (+14.4 pts gap) |
| 2022 | Barking and Dagenham | 51 | 9 | 17.6% | Labour Party · 79.7% of votes → 100.0% of seats (+20.3 pts gap) |
| 2026 | Huntingdonshire | 52 | 9 | 17.3% | Liberal Democrats · 26.4% of votes → 38.5% of seats (+12.0 pts gap) |
| 2018 | Huntingdonshire | 52 | 9 | 17.3% | Conservative Party · 47.9% of votes → 57.7% of seats (+9.8 pts gap) |
| 2022 | Vale of Glamorgan | 54 | 9 | 16.7% | Labour Party · 32.1% of votes → 46.3% of seats (+14.2 pts gap) |
| 2019 | Arun | 54 | 9 | 16.7% | Liberal Democrats · 30.2% of votes → 40.7% of seats (+10.6 pts gap) |
| 2025 | Leicestershire | 55 | 9 | 16.4% | Reform UK · 32.4% of votes → 45.5% of seats (+13.0 pts gap) |
| 2017 | Leicestershire | 55 | 9 | 16.4% | Conservative Party · 50.3% of votes → 65.5% of seats (+15.1 pts gap) |
| 2017 | Somerset | 55 | 9 | 16.4% | Conservative Party · 47.0% of votes → 63.6% of seats (+16.7 pts gap) |
| 2019 | Stockton-on-Tees | 56 | 9 | 16.1% | Labour Party · 32.6% of votes → 42.9% of seats (+10.2 pts gap) |
| 2026 | Swindon | 57 | 9 | 15.8% | Conservative Party · 29.7% of votes → 40.4% of seats (+10.7 pts gap) |
| 2025 | Worcestershire | 57 | 9 | 15.8% | Reform UK · 31.7% of votes → 47.4% of seats (+15.7 pts gap) |
| 2023 | Chelmsford | 57 | 9 | 15.8% | Liberal Democrats · 41.5% of votes → 57.9% of seats (+16.4 pts gap) |
| 2019 | East Devon | 57 | 9 | 15.8% | Independent · 23.1% of votes → 33.3% of seats (+10.2 pts gap) |
| 2017 | Warwickshire | 57 | 9 | 15.8% | Conservative Party · 49.3% of votes → 63.2% of seats (+13.9 pts gap) |
| 2024 | Rotherham | 59 | 9 | 15.3% | Labour Party · 42.8% of votes → 55.9% of seats (+13.1 pts gap) |
| 2021 | Rotherham | 59 | 9 | 15.3% | Labour Party · 41.4% of votes → 54.2% of seats (+12.9 pts gap) |
| 2019 | New Forest | 59 | 9 | 15.3% | Conservative Party · 58.6% of votes → 76.3% of seats (+17.6 pts gap) |
| 2023 | Lancaster | 61 | 9 | 14.8% | Labour Party · 31.8% of votes → 39.3% of seats (+7.6 pts gap) |
| 2021 | Cambridgeshire | 61 | 9 | 14.8% | Conservative Party · 39.0% of votes → 45.9% of seats (+6.9 pts gap) |
| 2026 | Lambeth | 63 | 9 | 14.3% | Green Party · 36.9% of votes → 46.0% of seats (+9.1 pts gap) |
| 2017 | Northumberland | 67 | 9 | 13.4% | Labour Party · 26.8% of votes → 35.8% of seats (+9.0 pts gap) |
| 2019 | Cheshire West and Chester | 70 | 9 | 12.9% | Labour Party · 36.7% of votes → 50.0% of seats (+13.3 pts gap) |
| 2021 | Shropshire | 73 | 9 | 12.3% | Conservative Party · 44.7% of votes → 57.5% of seats (+12.8 pts gap) |
| 2019 | Cheshire East | 81 | 9 | 11.1% | Conservative Party · 35.5% of votes → 40.7% of seats (+5.2 pts gap) |
| 2026 | Halton | 19 | 8 | 42.1% | Reform UK · 41.4% of votes → 84.2% of seats (+42.8 pts gap) |
| 2026 | Cheltenham | 20 | 8 | 40.0% | Liberal Democrats · 42.3% of votes → 85.0% of seats (+42.7 pts gap) |
| 2026 | Stockport | 21 | 8 | 38.1% | Liberal Democrats · 32.1% of votes → 61.9% of seats (+29.8 pts gap) |
| 2021 | Barnsley | 21 | 8 | 38.1% | Labour Party · 40.8% of votes → 81.0% of seats (+40.2 pts gap) |
| 2016 | Salford | 21 | 8 | 38.1% | Labour Party · 50.4% of votes → 90.5% of seats (+40.1 pts gap) |
| 2024 | Wakefield | 22 | 8 | 36.4% | Labour Party · 54.5% of votes → 95.5% of seats (+40.9 pts gap) |
| 2019 | Sandwell | 24 | 8 | 33.3% | Labour Party · 58.6% of votes → 100.0% of seats (+41.4 pts gap) |
| 2016 | Sunderland | 25 | 8 | 32.0% | Labour Party · 54.0% of votes → 88.0% of seats (+34.0 pts gap) |
| 2022 | Wigan | 26 | 8 | 30.8% | Labour Party · 53.0% of votes → 84.6% of seats (+31.6 pts gap) |
| 2018 | Sandwell | 26 | 8 | 30.8% | Labour Party · 67.9% of votes → 100.0% of seats (+32.1 pts gap) |
| 2019 | Sheffield | 28 | 8 | 28.6% | Labour Party · 31.6% of votes → 46.4% of seats (+14.8 pts gap) |
| 2024 | Rossendale | 30 | 8 | 26.7% | Labour Party · 42.8% of votes → 66.7% of seats (+23.8 pts gap) |
| 2022 | Manchester | 32 | 8 | 25.0% | Labour Party · 66.2% of votes → 93.8% of seats (+27.6 pts gap) |
| 2023 | Surrey Heath | 35 | 8 | 22.9% | Liberal Democrats · 48.8% of votes → 68.6% of seats (+19.7 pts gap) |
| 2022 | Leeds | 35 | 8 | 22.9% | Labour Party · 44.1% of votes → 62.9% of seats (+18.7 pts gap) |
| 2024 | Tunbridge Wells | 39 | 8 | 20.5% | Liberal Democrats · 34.2% of votes → 56.4% of seats (+22.3 pts gap) |
| 2023 | Uttlesford | 39 | 8 | 20.5% | RES · 36.3% of votes → 56.4% of seats (+20.1 pts gap) |
| 2023 | Chesterfield | 40 | 8 | 20.0% | Labour Party · 46.8% of votes → 70.0% of seats (+23.2 pts gap) |
| 2019 | Lichfield | 40 | 8 | 20.0% | Conservative Party · 49.0% of votes → 67.5% of seats (+18.5 pts gap) |
| 2017 | Isle of Wight | 40 | 8 | 20.0% | Conservative Party · 41.4% of votes → 62.5% of seats (+21.1 pts gap) |
| 2016 | Birmingham | 40 | 8 | 20.0% | Labour Party · 50.5% of votes → 75.0% of seats (+24.5 pts gap) |
| 2023 | Windsor & Maidenhead | 41 | 8 | 19.5% | W & M 1ST IND · 10.2% of votes → 17.1% of seats (+6.8 pts gap) |
| 2023 | Stratford On Avon | 41 | 8 | 19.5% | Liberal Democrats · 42.4% of votes → 61.0% of seats (+18.5 pts gap) |
| 2019 | Windsor and Maidenhead | 41 | 8 | 19.5% | Conservative Party · 42.8% of votes → 56.1% of seats (+13.3 pts gap) |
| 2022 | Tower Hamlets | 42 | 8 | 19.0% | Aspire · 36.9% of votes → 54.8% of seats (+17.8 pts gap) |
| 2019 | East Hampshire | 42 | 8 | 19.0% | Conservative Party · 53.8% of votes → 73.8% of seats (+20.0 pts gap) |
| 2019 | North Devon | 42 | 8 | 19.0% | Liberal Democrats · 37.5% of votes → 50.0% of seats (+12.5 pts gap) |
| 2019 | Rushcliffe | 42 | 8 | 19.0% | Conservative Party · 43.3% of votes → 64.3% of seats (+21.0 pts gap) |
| 2023 | Wychavon | 43 | 8 | 18.6% | Conservative Party · 46.6% of votes → 67.4% of seats (+20.8 pts gap) |
| 2023 | Stoke On Trent | 44 | 8 | 18.2% | Labour Party · 46.6% of votes → 65.9% of seats (+19.4 pts gap) |
| 2023 | Rushcliffe | 44 | 8 | 18.2% | Conservative Party · 40.7% of votes → 56.8% of seats (+16.1 pts gap) |
| 2019 | Warwick | 44 | 8 | 18.2% | Conservative Party · 29.4% of votes → 43.2% of seats (+13.8 pts gap) |
| 2017 | Torfaen | 44 | 8 | 18.2% | Labour Party · 47.6% of votes → 65.9% of seats (+18.3 pts gap) |
| 2018 | Bexley | 45 | 8 | 17.8% | Conservative Party · 55.4% of votes → 75.6% of seats (+20.1 pts gap) |
| 2023 | Teignbridge | 47 | 8 | 17.0% | Liberal Democrats · 38.4% of votes → 55.3% of seats (+16.9 pts gap) |
| 2023 | York | 47 | 8 | 17.0% | Liberal Democrats · 30.5% of votes → 40.4% of seats (+9.9 pts gap) |
| 2022 | Reading | 48 | 8 | 16.7% | Labour Party · 48.9% of votes → 66.7% of seats (+17.8 pts gap) |
| 2019 | Sedgemoor | 48 | 8 | 16.7% | Conservative Party · 46.6% of votes → 58.3% of seats (+11.8 pts gap) |
| 2023 | Dacorum | 51 | 8 | 15.7% | Liberal Democrats · 42.0% of votes → 54.9% of seats (+12.9 pts gap) |
| 2018 | South Lakeland | 51 | 8 | 15.7% | Liberal Democrats · 41.0% of votes → 56.9% of seats (+15.8 pts gap) |
| 2019 | Herefordshire | 53 | 8 | 15.1% | IOCH · 8.6% of votes → 15.1% of seats (+6.4 pts gap) |
| 2024 | Epping Forest | 54 | 8 | 14.8% | Conservative Party · 42.1% of votes → 53.7% of seats (+11.6 pts gap) |
| 2023 | Leicester | 54 | 8 | 14.8% | Labour Party · 40.4% of votes → 57.4% of seats (+17.0 pts gap) |
| 2021 | Basingstoke & Deane | 54 | 8 | 14.8% | Conservative Party · 48.8% of votes → 61.1% of seats (+12.3 pts gap) |
| 2022 | Sutton | 55 | 8 | 14.5% | Liberal Democrats · 39.5% of votes → 52.7% of seats (+13.2 pts gap) |
| 2022 | Conwy | 55 | 8 | 14.5% | Independent · 32.3% of votes → 40.0% of seats (+7.7 pts gap) |
| 2019 | West Suffolk | 56 | 8 | 14.3% | Independent · 19.7% of votes → 26.8% of seats (+7.1 pts gap) |
| 2026 | Haringey | 57 | 8 | 14.0% | Green Party · 35.4% of votes → 49.1% of seats (+13.7 pts gap) |
| 2022 | Wandsworth | 58 | 8 | 13.8% | Labour Party · 46.3% of votes → 60.3% of seats (+14.1 pts gap) |
| 2018 | Wandsworth | 60 | 8 | 13.3% | Conservative Party · 42.1% of votes → 55.0% of seats (+12.9 pts gap) |
| 2018 | Barnet | 63 | 8 | 12.7% | Conservative Party · 46.9% of votes → 60.3% of seats (+13.4 pts gap) |
| 2017 | Derbyshire | 64 | 8 | 12.5% | Conservative Party · 43.9% of votes → 57.8% of seats (+13.9 pts gap) |
| 2018 | Hillingdon | 65 | 8 | 12.3% | Conservative Party · 54.2% of votes → 67.7% of seats (+13.4 pts gap) |
| 2018 | Croydon | 70 | 8 | 11.4% | Labour Party · 46.4% of votes → 58.6% of seats (+12.2 pts gap) |
| 2016 | Castle Point | 14 | 7 | 50.0% | Conservative Party · 37.3% of votes → 64.3% of seats (+27.0 pts gap) |
| 2026 | Eastleigh | 15 | 7 | 46.7% | Liberal Democrats · 41.2% of votes → 93.3% of seats (+52.1 pts gap) |
| 2026 | North East Lincolnshire | 15 | 7 | 46.7% | Reform UK · 45.9% of votes → 93.3% of seats (+47.5 pts gap) |
| 2026 | Winchester | 15 | 7 | 46.7% | Liberal Democrats · 41.6% of votes → 86.7% of seats (+45.1 pts gap) |
| 2016 | South Tyneside | 18 | 7 | 38.9% | Labour Party · 56.5% of votes → 100.0% of seats (+43.5 pts gap) |
| 2024 | Plymouth | 19 | 7 | 36.8% | Labour Party · 44.2% of votes → 78.9% of seats (+34.7 pts gap) |
| 2019 | Tameside | 19 | 7 | 36.8% | Labour Party · 46.2% of votes → 89.5% of seats (+43.2 pts gap) |
| 2021 | South Tyneside | 20 | 7 | 35.0% | Labour Party · 43.4% of votes → 80.0% of seats (+36.6 pts gap) |
| 2019 | North Tyneside | 20 | 7 | 35.0% | Labour Party · 49.1% of votes → 85.0% of seats (+35.9 pts gap) |
| 2019 | Salford | 20 | 7 | 35.0% | Labour Party · 41.6% of votes → 80.0% of seats (+38.4 pts gap) |
| 2016 | Tameside | 20 | 7 | 35.0% | Labour Party · 51.8% of votes → 90.0% of seats (+38.2 pts gap) |
| 2023 | Wakefield | 21 | 7 | 33.3% | Labour Party · 52.7% of votes → 95.2% of seats (+42.5 pts gap) |
| 2024 | Sandwell | 24 | 7 | 29.2% | Labour Party · 56.9% of votes → 91.7% of seats (+34.8 pts gap) |
| 2023 | Sandwell | 24 | 7 | 29.2% | Labour Party · 57.8% of votes → 91.7% of seats (+33.8 pts gap) |
| 2021 | Gateshead | 24 | 7 | 29.2% | Labour Party · 46.7% of votes → 79.2% of seats (+32.5 pts gap) |
| 2016 | Sandwell | 24 | 7 | 29.2% | Labour Party · 67.0% of votes → 100.0% of seats (+33.0 pts gap) |
| 2021 | Dudley | 26 | 7 | 26.9% | Conservative Party · 57.1% of votes → 88.5% of seats (+31.4 pts gap) |
| 2024 | Redditch | 27 | 7 | 25.9% | Labour Party · 48.2% of votes → 77.8% of seats (+29.6 pts gap) |
| 2022 | Newcastle upon Tyne | 27 | 7 | 25.9% | Labour Party · 44.1% of votes → 70.4% of seats (+26.2 pts gap) |
| 2019 | Hambleton | 27 | 7 | 25.9% | Conservative Party · 59.7% of votes → 85.2% of seats (+25.5 pts gap) |
| 2021 | Newcastle Upon Tyne | 28 | 7 | 25.0% | Labour Party · 39.2% of votes → 64.3% of seats (+25.1 pts gap) |
| 2023 | Bradford | 30 | 7 | 23.3% | Labour Party · 47.0% of votes → 73.3% of seats (+26.3 pts gap) |
| 2026 | Manchester | 32 | 7 | 21.9% | Green Party · 37.3% of votes → 56.3% of seats (+18.9 pts gap) |
| 2018 | Hastings | 32 | 7 | 21.9% | Labour Party · 49.6% of votes → 75.0% of seats (+25.4 pts gap) |
| 2024 | Leeds | 33 | 7 | 21.2% | Labour Party · 43.3% of votes → 57.6% of seats (+14.2 pts gap) |
| 2023 | Manchester | 33 | 7 | 21.2% | Labour Party · 65.2% of votes → 90.9% of seats (+25.7 pts gap) |
| 2019 | Harborough | 33 | 7 | 21.2% | Conservative Party · 41.8% of votes → 63.6% of seats (+21.8 pts gap) |
| 2019 | Wyre Forest | 33 | 7 | 21.2% | Conservative Party · 31.6% of votes → 42.4% of seats (+10.8 pts gap) |
| 2016 | Leeds | 33 | 7 | 21.2% | Labour Party · 43.0% of votes → 63.6% of seats (+20.6 pts gap) |
| 2023 | Cotswold | 34 | 7 | 20.6% | Liberal Democrats · 46.2% of votes → 64.7% of seats (+18.5 pts gap) |
| 2021 | Leeds | 34 | 7 | 20.6% | Labour Party · 41.6% of votes → 55.9% of seats (+14.3 pts gap) |
| 2022 | Isle of Anglesey | 35 | 7 | 20.0% | Plaid Cymru · 40.8% of votes → 60.0% of seats (+19.2 pts gap) |
| 2023 | Forest Of Dean | 38 | 7 | 18.4% | Green Party · 28.4% of votes → 39.5% of seats (+11.1 pts gap) |
| 2023 | Tewkesbury | 38 | 7 | 18.4% | Independent · 9.1% of votes → 18.4% of seats (+9.4 pts gap) |
| 2019 | Newark and Sherwood | 38 | 7 | 18.4% | Conservative Party · 47.9% of votes → 68.4% of seats (+20.5 pts gap) |
| 2019 | Tewkesbury | 38 | 7 | 18.4% | Conservative Party · 41.2% of votes → 60.5% of seats (+19.3 pts gap) |
| 2021 | Isle Of Wight | 39 | 7 | 17.9% | Independent · 19.4% of votes → 28.2% of seats (+8.8 pts gap) |
| 2019 | Hertsmere | 39 | 7 | 17.9% | Conservative Party · 54.2% of votes → 74.4% of seats (+20.2 pts gap) |
| 2023 | North Devon | 41 | 7 | 17.1% | Liberal Democrats · 39.2% of votes → 51.2% of seats (+12.1 pts gap) |
| 2019 | Lewes | 41 | 7 | 17.1% | Conservative Party · 27.1% of votes → 46.3% of seats (+19.3 pts gap) |
| 2019 | Runnymede | 41 | 7 | 17.1% | Conservative Party · 47.0% of votes → 63.4% of seats (+16.4 pts gap) |
| 2023 | Blackpool | 42 | 7 | 16.7% | Labour Party · 48.3% of votes → 66.7% of seats (+18.4 pts gap) |
| 2021 | Chorley | 42 | 7 | 16.7% | Labour Party · 49.3% of votes → 69.0% of seats (+19.7 pts gap) |
| 2019 | Dartford | 42 | 7 | 16.7% | Conservative Party · 52.8% of votes → 69.0% of seats (+16.3 pts gap) |
| 2023 | West Berkshire | 43 | 7 | 16.3% | Liberal Democrats · 48.9% of votes → 67.4% of seats (+18.5 pts gap) |
| 2023 | Test Valley | 43 | 7 | 16.3% | Conservative Party · 42.7% of votes → 60.5% of seats (+17.7 pts gap) |
| 2019 | High Peak | 43 | 7 | 16.3% | Labour Party · 34.9% of votes → 51.2% of seats (+16.2 pts gap) |
| 2023 | Broxtowe | 44 | 7 | 15.9% | Labour Party · 43.9% of votes → 59.1% of seats (+15.2 pts gap) |
| 2019 | South Staffordshire | 45 | 7 | 15.6% | Conservative Party · 57.4% of votes → 73.3% of seats (+16.0 pts gap) |
| 2023 | South Norfolk | 46 | 7 | 15.2% | Conservative Party · 39.2% of votes → 52.2% of seats (+12.9 pts gap) |
| 2023 | Erewash | 47 | 7 | 14.9% | Labour Party · 43.6% of votes → 59.6% of seats (+16.0 pts gap) |
| 2023 | Tendring | 48 | 7 | 14.6% | Independent · 24.1% of votes → 33.3% of seats (+9.3 pts gap) |
| 2019 | Chesterfield | 48 | 7 | 14.6% | Labour Party · 43.5% of votes → 58.3% of seats (+14.8 pts gap) |
| 2019 | Luton | 48 | 7 | 14.6% | Liberal Democrats · 17.2% of votes → 25.0% of seats (+7.8 pts gap) |
| 2019 | Tendring | 48 | 7 | 14.6% | UK Independence Party (UKIP) · 4.9% of votes → 10.4% of seats (+5.5 pts gap) |
| 2023 | Breckland | 49 | 7 | 14.3% | Conservative Party · 44.6% of votes → 61.2% of seats (+16.6 pts gap) |
| 2019 | Breckland | 49 | 7 | 14.3% | Conservative Party · 58.3% of votes → 75.5% of seats (+17.3 pts gap) |
| 2023 | East Hertfordshire | 50 | 7 | 14.0% | Green Party · 28.4% of votes → 38.0% of seats (+9.6 pts gap) |
| 2023 | South Ribble | 50 | 7 | 14.0% | Labour Party · 42.7% of votes → 58.0% of seats (+15.3 pts gap) |
| 2023 | North Somerset | 50 | 7 | 14.0% | Independent · 10.7% of votes → 16.0% of seats (+5.3 pts gap) |
| 2023 | Darlington | 50 | 7 | 14.0% | Labour Party · 35.0% of votes → 48.0% of seats (+13.0 pts gap) |
| 2019 | North Somerset | 50 | 7 | 14.0% | Independent · 16.8% of votes → 26.0% of seats (+9.2 pts gap) |
| 2026 | Solihull | 51 | 7 | 13.7% | Conservative Party · 35.4% of votes → 47.1% of seats (+11.6 pts gap) |
| 2024 | Stroud | 51 | 7 | 13.7% | Labour Party · 31.0% of votes → 39.2% of seats (+8.2 pts gap) |
| 2022 | Bridgend | 51 | 7 | 13.7% | Labour Party · 43.6% of votes → 52.9% of seats (+9.3 pts gap) |
| 2019 | Fylde | 51 | 7 | 13.7% | Independent · 25.0% of votes → 33.3% of seats (+8.4 pts gap) |
| 2016 | Colchester | 51 | 7 | 13.7% | Conservative Party · 37.5% of votes → 43.1% of seats (+5.6 pts gap) |
| 2021 | Gloucestershire | 53 | 7 | 13.2% | Conservative Party · 43.9% of votes → 52.8% of seats (+8.9 pts gap) |
| 2017 | Conwy | 53 | 7 | 13.2% | Plaid Cymru · 7.8% of votes → 15.1% of seats (+7.3 pts gap) |
| 2017 | Gloucestershire | 53 | 7 | 13.2% | Conservative Party · 45.1% of votes → 58.5% of seats (+13.4 pts gap) |
| 2023 | Medway | 59 | 7 | 11.9% | Labour Party · 45.0% of votes → 55.9% of seats (+11.0 pts gap) |
| 2023 | Bolton | 60 | 7 | 11.7% | H & B 1ST · 4.8% of votes → 10.0% of seats (+5.2 pts gap) |
| 2023 | West Suffolk | 60 | 7 | 11.7% | WS IND · 7.9% of votes → 15.0% of seats (+7.1 pts gap) |
| 2017 | Neath Port Talbot | 60 | 7 | 11.7% | Labour Party · 51.0% of votes → 65.0% of seats (+14.0 pts gap) |
| 2019 | South Gloucestershire | 61 | 7 | 11.5% | Conservative Party · 41.6% of votes → 54.1% of seats (+12.5 pts gap) |
| 2026 | Southwark | 63 | 7 | 11.1% | Labour Party · 36.2% of votes → 46.0% of seats (+9.9 pts gap) |
| 2021 | Oxfordshire | 63 | 7 | 11.1% | Liberal Democrats · 25.9% of votes → 33.3% of seats (+7.4 pts gap) |
| 2017 | Oxfordshire | 63 | 7 | 11.1% | Conservative Party · 41.2% of votes → 49.2% of seats (+8.0 pts gap) |
| 2017 | Lancashire | 84 | 7 | 8.3% | Conservative Party · 45.1% of votes → 54.8% of seats (+9.6 pts gap) |
| 2026 | Birmingham | 101 | 7 | 6.9% | Reform UK · 19.5% of votes → 22.8% of seats (+3.3 pts gap) |
| 2017 | Cornwall | 123 | 7 | 5.7% | Independent · 20.0% of votes → 24.4% of seats (+4.4 pts gap) |
| 2026 | Watford | 12 | 6 | 50.0% | Liberal Democrats · 44.8% of votes → 100.0% of seats (+55.2 pts gap) |
| 2026 | Cannock Chase | 13 | 6 | 46.2% | Reform UK · 53.6% of votes → 100.0% of seats (+46.4 pts gap) |
| 2016 | Worthing | 13 | 6 | 46.2% | Conservative Party · 38.6% of votes → 84.6% of seats (+46.0 pts gap) |
| 2024 | Mole Valley | 14 | 6 | 42.9% | Liberal Democrats · 47.4% of votes → 85.7% of seats (+38.3 pts gap) |
| 2026 | Rochford | 15 | 6 | 40.0% | Reform UK · 40.8% of votes → 86.7% of seats (+45.9 pts gap) |
| 2026 | Tunbridge Wells | 15 | 6 | 40.0% | Liberal Democrats · 37.9% of votes → 73.3% of seats (+35.4 pts gap) |
| 2016 | Eastleigh | 15 | 6 | 40.0% | Liberal Democrats · 46.1% of votes → 86.7% of seats (+40.6 pts gap) |
| 2024 | Elmbridge | 16 | 6 | 37.5% | HW and WG · 4.2% of votes → 6.3% of seats (+2.0 pts gap) |
| 2026 | Blackburn with Darwen | 17 | 6 | 35.3% | Reform UK · 29.6% of votes → 52.9% of seats (+23.4 pts gap) |
| 2021 | Welwyn Hatfield | 17 | 6 | 35.3% | Conservative Party · 48.7% of votes → 88.2% of seats (+39.5 pts gap) |
| 2024 | Ipswich | 18 | 6 | 33.3% | Labour Party · 46.5% of votes → 83.3% of seats (+36.8 pts gap) |
| 2026 | Nuneaton and Bedworth | 19 | 6 | 31.6% | Reform UK · 43.3% of votes → 78.9% of seats (+35.7 pts gap) |
| 2026 | Plymouth | 19 | 6 | 31.6% | Reform UK · 37.2% of votes → 73.7% of seats (+36.5 pts gap) |
| 2023 | Plymouth | 19 | 6 | 31.6% | Labour Party · 45.3% of votes → 78.9% of seats (+33.6 pts gap) |
| 2023 | Swindon | 19 | 6 | 31.6% | Labour Party · 51.9% of votes → 84.2% of seats (+32.4 pts gap) |
| 2021 | Tameside | 19 | 6 | 31.6% | Labour Party · 50.8% of votes → 84.2% of seats (+33.4 pts gap) |
| 2019 | South Tyneside | 19 | 6 | 31.6% | Labour Party · 41.9% of votes → 73.7% of seats (+31.8 pts gap) |
| 2026 | Rochdale | 20 | 6 | 30.0% | Reform UK · 35.0% of votes → 65.0% of seats (+30.0 pts gap) |
| 2023 | Milton Keynes | 20 | 6 | 30.0% | Labour Party · 38.2% of votes → 60.0% of seats (+21.8 pts gap) |
| 2022 | North Tyneside | 20 | 6 | 30.0% | Labour Party · 54.9% of votes → 90.0% of seats (+35.1 pts gap) |
| 2021 | Cheltenham | 20 | 6 | 30.0% | Liberal Democrats · 42.6% of votes → 70.0% of seats (+27.4 pts gap) |
| 2021 | Rochdale | 20 | 6 | 30.0% | Labour Party · 49.4% of votes → 80.0% of seats (+30.6 pts gap) |
| 2019 | Oldham | 20 | 6 | 30.0% | Labour Party · 40.6% of votes → 75.0% of seats (+34.4 pts gap) |
| 2018 | North Tyneside | 20 | 6 | 30.0% | Labour Party · 56.8% of votes → 90.0% of seats (+33.2 pts gap) |
| 2016 | Cheltenham | 20 | 6 | 30.0% | Liberal Democrats · 45.1% of votes → 75.0% of seats (+29.9 pts gap) |
| 2016 | Wolverhampton | 20 | 6 | 30.0% | Labour Party · 53.1% of votes → 90.0% of seats (+36.9 pts gap) |
| 2026 | Salford | 21 | 6 | 28.6% | Reform UK · 34.7% of votes → 61.9% of seats (+27.2 pts gap) |
| 2024 | Barnsley | 21 | 6 | 28.6% | Labour Party · 49.3% of votes → 81.0% of seats (+31.7 pts gap) |
| 2024 | St Albans | 21 | 6 | 28.6% | Liberal Democrats · 49.9% of votes → 81.0% of seats (+31.1 pts gap) |
| 2024 | Trafford | 21 | 6 | 28.6% | Labour Party · 41.9% of votes → 71.4% of seats (+29.5 pts gap) |
| 2022 | Cheltenham | 21 | 6 | 28.6% | Liberal Democrats · 55.4% of votes → 85.7% of seats (+30.3 pts gap) |
| 2022 | Wakefield | 21 | 6 | 28.6% | Labour Party · 51.7% of votes → 81.0% of seats (+29.3 pts gap) |
| 2018 | Cheltenham | 21 | 6 | 28.6% | Liberal Democrats · 45.6% of votes → 81.0% of seats (+35.3 pts gap) |
| 2016 | Wakefield | 21 | 6 | 28.6% | Labour Party · 53.4% of votes → 90.5% of seats (+37.1 pts gap) |
| 2019 | Gateshead | 22 | 6 | 27.3% | Labour Party · 44.5% of votes → 77.3% of seats (+32.8 pts gap) |
| 2018 | Wolverhampton | 22 | 6 | 27.3% | Labour Party · 57.8% of votes → 86.4% of seats (+28.6 pts gap) |
| 2021 | Peterborough | 23 | 6 | 26.1% | Conservative Party · 44.6% of votes → 69.6% of seats (+25.0 pts gap) |
| 2021 | North Tyneside | 23 | 6 | 26.1% | Labour Party · 48.6% of votes → 78.3% of seats (+29.7 pts gap) |
| 2019 | Sefton | 23 | 6 | 26.1% | Labour Party · 43.1% of votes → 69.6% of seats (+26.5 pts gap) |
| 2018 | Gateshead | 23 | 6 | 26.1% | Labour Party · 54.2% of votes → 82.6% of seats (+28.4 pts gap) |
| 2016 | Sefton | 23 | 6 | 26.1% | Liberal Democrats · 17.3% of votes → 30.4% of seats (+13.1 pts gap) |
| 2022 | Sandwell | 24 | 6 | 25.0% | Labour Party · 57.5% of votes → 87.5% of seats (+30.0 pts gap) |
| 2021 | Sefton | 24 | 6 | 25.0% | Labour Party · 46.4% of votes → 79.2% of seats (+32.7 pts gap) |
| 2018 | Oxford | 24 | 6 | 25.0% | Labour Party · 47.8% of votes → 75.0% of seats (+27.2 pts gap) |
| 2016 | Oxford | 24 | 6 | 25.0% | Labour Party · 47.0% of votes → 75.0% of seats (+28.0 pts gap) |
| 2024 | Sunderland | 25 | 6 | 24.0% | Labour Party · 45.5% of votes → 72.0% of seats (+26.5 pts gap) |
| 2016 | Wigan | 25 | 6 | 24.0% | Labour Party · 49.8% of votes → 76.0% of seats (+26.2 pts gap) |
| 2023 | Oadby & Wigston | 26 | 6 | 23.1% | Liberal Democrats · 51.1% of votes → 73.1% of seats (+22.0 pts gap) |
| 2019 | Oadby and Wigston | 26 | 6 | 23.1% | Liberal Democrats · 66.7% of votes → 92.3% of seats (+25.6 pts gap) |
| 2016 | Newcastle upon Tyne | 26 | 6 | 23.1% | Labour Party · 44.5% of votes → 69.2% of seats (+24.7 pts gap) |
| 2019 | Newcastle upon Tyne | 27 | 6 | 22.2% | Labour Party · 38.4% of votes → 63.0% of seats (+24.6 pts gap) |
| 2022 | Sheffield | 28 | 6 | 21.4% | Labour Party · 40.6% of votes → 53.6% of seats (+12.9 pts gap) |
| 2018 | Sheffield | 28 | 6 | 21.4% | Labour Party · 40.3% of votes → 57.1% of seats (+16.9 pts gap) |
| 2019 | Liverpool | 30 | 6 | 20.0% | Labour Party · 58.8% of votes → 83.3% of seats (+24.6 pts gap) |
| 2021 | Liverpool | 31 | 6 | 19.4% | Labour Party · 50.0% of votes → 74.2% of seats (+24.2 pts gap) |
| 2024 | Fareham | 32 | 6 | 18.8% | Conservative Party · 45.9% of votes → 68.8% of seats (+22.9 pts gap) |
| 2019 | Dover | 32 | 6 | 18.8% | Conservative Party · 43.7% of votes → 59.4% of seats (+15.7 pts gap) |
| 2023 | Wyre Forest | 33 | 6 | 18.2% | Conservative Party · 41.7% of votes → 60.6% of seats (+19.0 pts gap) |
| 2019 | Leeds | 33 | 6 | 18.2% | Labour Party · 38.2% of votes → 57.6% of seats (+19.4 pts gap) |
| 2024 | Worcester | 35 | 6 | 17.1% | Labour Party · 29.6% of votes → 48.6% of seats (+19.0 pts gap) |
| 2019 | Ashfield | 35 | 6 | 17.1% | Ashfield · 64.6% of votes → 85.7% of seats (+21.1 pts gap) |
| 2023 | South Derbyshire | 36 | 6 | 16.7% | Labour Party · 48.7% of votes → 63.9% of seats (+15.2 pts gap) |
| 2019 | Barrow-in-Furness | 36 | 6 | 16.7% | Labour Party · 50.9% of votes → 66.7% of seats (+15.8 pts gap) |
| 2019 | Mansfield | 36 | 6 | 16.7% | Independent · 7.5% of votes → 16.7% of seats (+9.2 pts gap) |
| 2019 | Torbay | 36 | 6 | 16.7% | Liberal Democrats · 27.8% of votes → 36.1% of seats (+8.3 pts gap) |
| 2023 | Rother | 38 | 6 | 15.8% | Labour Party · 14.2% of votes → 21.1% of seats (+6.9 pts gap) |
| 2021 | Gloucester | 39 | 6 | 15.4% | Conservative Party · 47.3% of votes → 66.7% of seats (+19.4 pts gap) |
| 2019 | Derbyshire Dales | 39 | 6 | 15.4% | Conservative Party · 40.1% of votes → 51.3% of seats (+11.2 pts gap) |
| 2019 | Spelthorne | 39 | 6 | 15.4% | Conservative Party · 46.4% of votes → 59.0% of seats (+12.6 pts gap) |
| 2022 | Torfaen | 40 | 6 | 15.0% | Labour Party · 57.4% of votes → 75.0% of seats (+17.6 pts gap) |
| 2023 | Gedling | 41 | 6 | 14.6% | Labour Party · 52.3% of votes → 68.3% of seats (+16.0 pts gap) |
| 2019 | Ashford | 41 | 6 | 14.6% | Conservative Party · 39.1% of votes → 48.8% of seats (+9.7 pts gap) |
| 2017 | Blaenau Gwent | 42 | 6 | 14.3% | Independent · 52.7% of votes → 66.7% of seats (+13.9 pts gap) |
| 2019 | West Berkshire | 43 | 6 | 14.0% | Conservative Party · 42.8% of votes → 55.8% of seats (+13.0 pts gap) |
| 2023 | Warwick | 44 | 6 | 13.6% | Green Party · 26.3% of votes → 31.8% of seats (+5.5 pts gap) |
| 2019 | Broxtowe | 44 | 6 | 13.6% | Conservative Party · 35.7% of votes → 45.5% of seats (+9.8 pts gap) |
| 2019 | Allerdale | 45 | 6 | 13.3% | Independent · 29.8% of votes → 42.2% of seats (+12.4 pts gap) |
| 2016 | Knowsley | 45 | 6 | 13.3% | Labour Party · 74.5% of votes → 93.3% of seats (+18.9 pts gap) |
| 2016 | Winchester | 45 | 6 | 13.3% | Conservative Party · 45.8% of votes → 55.6% of seats (+9.8 pts gap) |
| 2017 | Dorset | 46 | 6 | 13.0% | Conservative Party · 53.7% of votes → 69.6% of seats (+15.8 pts gap) |
| 2023 | Swale | 47 | 6 | 12.8% | Labour Party · 25.0% of votes → 31.9% of seats (+6.9 pts gap) |
| 2023 | Broadland | 47 | 6 | 12.8% | Conservative Party · 38.2% of votes → 44.7% of seats (+6.4 pts gap) |
| 2023 | New Forest | 48 | 6 | 12.5% | Conservative Party · 42.1% of votes → 54.2% of seats (+12.1 pts gap) |
| 2022 | Huntingdonshire | 48 | 6 | 12.5% | Independent · 13.3% of votes → 22.9% of seats (+9.6 pts gap) |
| 2019 | Preston | 48 | 6 | 12.5% | Labour Party · 47.6% of votes → 62.5% of seats (+14.9 pts gap) |
| 2021 | East Sussex | 50 | 6 | 12.0% | Conservative Party · 42.0% of votes → 54.0% of seats (+12.0 pts gap) |
| 2019 | East Lindsey | 50 | 6 | 12.0% | Independent · 15.8% of votes → 22.0% of seats (+6.2 pts gap) |
| 2023 | Herefordshire | 53 | 6 | 11.3% | Conservative Party · 34.6% of votes → 39.6% of seats (+5.0 pts gap) |
| 2019 | North East Derbyshire | 53 | 6 | 11.3% | Conservative Party · 46.8% of votes → 56.6% of seats (+9.8 pts gap) |
| 2022 | Westminster | 54 | 6 | 11.1% | Labour Party · 48.0% of votes → 57.4% of seats (+9.4 pts gap) |
| 2023 | Staffordshire Moorlands | 55 | 6 | 10.9% | Labour Party · 36.7% of votes → 43.6% of seats (+6.9 pts gap) |
| 2023 | East Suffolk | 55 | 6 | 10.9% | Liberal Democrats · 15.8% of votes → 20.0% of seats (+4.2 pts gap) |
| 2023 | Stockton-on-Tees | 56 | 6 | 10.7% | Labour Party · 33.6% of votes → 39.3% of seats (+5.7 pts gap) |
| 2023 | Thanet | 56 | 6 | 10.7% | Labour Party · 40.2% of votes → 53.6% of seats (+13.3 pts gap) |
| 2019 | Thanet | 56 | 6 | 10.7% | Conservative Party · 38.1% of votes → 44.6% of seats (+6.5 pts gap) |
| 2019 | Lancaster | 60 | 6 | 10.0% | MBI · 12.9% of votes → 23.3% of seats (+10.4 pts gap) |
| 2018 | Merton | 60 | 6 | 10.0% | Labour Party · 46.9% of votes → 56.7% of seats (+9.7 pts gap) |
| 2024 | Bristol, City of | 70 | 6 | 8.6% | Green Party · 39.7% of votes → 48.6% of seats (+8.9 pts gap) |
| 2024 | Dudley | 72 | 6 | 8.3% | Conservative Party · 42.0% of votes → 47.2% of seats (+5.3 pts gap) |
| 2026 | Hart | 11 | 5 | 45.5% | Community Campaign (Hart) · 14.3% of votes → 36.4% of seats (+22.0 pts gap) |
| 2019 | Havant | 11 | 5 | 45.5% | Conservative Party · 43.9% of votes → 100.0% of seats (+56.1 pts gap) |
| 2019 | Lincoln | 11 | 5 | 45.5% | Labour Party · 44.2% of votes → 90.9% of seats (+46.7 pts gap) |
| 2026 | Hartlepool | 12 | 5 | 41.7% | Reform UK · 49.7% of votes → 100.0% of seats (+50.3 pts gap) |
| 2024 | Watford | 12 | 5 | 41.7% | Liberal Democrats · 48.2% of votes → 91.7% of seats (+43.5 pts gap) |
| 2021 | Eastleigh | 12 | 5 | 41.7% | Liberal Democrats · 44.7% of votes → 83.3% of seats (+38.7 pts gap) |
| 2026 | Crawley | 13 | 5 | 38.5% | Reform UK · 33.4% of votes → 76.9% of seats (+43.5 pts gap) |
| 2019 | Eastleigh | 13 | 5 | 38.5% | Liberal Democrats · 52.1% of votes → 92.3% of seats (+40.2 pts gap) |
| 2018 | Norwich | 13 | 5 | 38.5% | Labour Party · 49.2% of votes → 92.3% of seats (+43.1 pts gap) |
| 2016 | Norwich | 13 | 5 | 38.5% | Labour Party · 44.3% of votes → 84.6% of seats (+40.3 pts gap) |
| 2026 | Portsmouth | 14 | 5 | 35.7% | Liberal Democrats · 29.5% of votes → 57.1% of seats (+27.6 pts gap) |
| 2023 | Castle Point | 14 | 5 | 35.7% | Canvey Island Independent Party · 20.2% of votes → 42.9% of seats (+22.7 pts gap) |
| 2022 | Eastleigh | 14 | 5 | 35.7% | Liberal Democrats · 50.9% of votes → 92.9% of seats (+41.9 pts gap) |
| 2022 | Havant | 14 | 5 | 35.7% | Conservative Party · 48.1% of votes → 85.7% of seats (+37.6 pts gap) |
| 2022 | Chorley | 14 | 5 | 35.7% | Labour Party · 55.8% of votes → 92.9% of seats (+37.1 pts gap) |
| 2021 | Havant | 14 | 5 | 35.7% | Conservative Party · 59.2% of votes → 100.0% of seats (+40.8 pts gap) |
| 2026 | Burnley | 15 | 5 | 33.3% | Reform UK · 43.1% of votes → 73.3% of seats (+30.2 pts gap) |
| 2019 | Portsmouth | 15 | 5 | 33.3% | Conservative Party · 26.3% of votes → 46.7% of seats (+20.4 pts gap) |
| 2016 | Runnymede | 15 | 5 | 33.3% | Conservative Party · 51.5% of votes → 86.7% of seats (+35.1 pts gap) |
| 2026 | Bury | 16 | 5 | 31.3% | Labour Party · 26.8% of votes → 43.8% of seats (+16.9 pts gap) |
| 2026 | Fareham | 16 | 5 | 31.3% | Conservative Party · 39.0% of votes → 68.8% of seats (+29.7 pts gap) |
| 2026 | Ipswich | 16 | 5 | 31.3% | Reform UK · 31.7% of votes → 62.5% of seats (+30.8 pts gap) |
| 2024 | Adur | 16 | 5 | 31.3% | Labour Party · 48.5% of votes → 81.3% of seats (+32.7 pts gap) |
| 2023 | Ipswich | 16 | 5 | 31.3% | Labour Party · 43.0% of votes → 75.0% of seats (+32.0 pts gap) |
| 2023 | Elmbridge | 16 | 5 | 31.3% | Liberal Democrats · 38.9% of votes → 56.3% of seats (+17.3 pts gap) |
| 2022 | Fareham | 16 | 5 | 31.3% | Conservative Party · 44.9% of votes → 75.0% of seats (+30.1 pts gap) |
| 2019 | Epping Forest | 16 | 5 | 31.3% | Conservative Party · 50.5% of votes → 81.3% of seats (+30.8 pts gap) |
| 2018 | Tunbridge Wells | 16 | 5 | 31.3% | Conservative Party · 42.8% of votes → 75.0% of seats (+32.2 pts gap) |
| 2016 | Tunbridge Wells | 16 | 5 | 31.3% | Conservative Party · 47.5% of votes → 81.3% of seats (+33.7 pts gap) |
| 2026 | Southampton | 17 | 5 | 29.4% | Reform UK · 25.7% of votes → 47.1% of seats (+21.4 pts gap) |
| 2022 | Ipswich | 17 | 5 | 29.4% | Labour Party · 46.8% of votes → 82.4% of seats (+35.6 pts gap) |
| 2021 | St Helens | 17 | 5 | 29.4% | Labour Party · 41.9% of votes → 70.6% of seats (+28.7 pts gap) |
| 2018 | Chorley | 17 | 5 | 29.4% | Labour Party · 54.3% of votes → 82.4% of seats (+28.0 pts gap) |
| 2016 | Hastings | 17 | 5 | 29.4% | Labour Party · 50.2% of votes → 82.4% of seats (+32.2 pts gap) |
| 2016 | Reigate and Banstead | 17 | 5 | 29.4% | Conservative Party · 42.6% of votes → 70.6% of seats (+28.0 pts gap) |
| 2023 | Halton | 18 | 5 | 27.8% | Labour Party · 64.4% of votes → 94.4% of seats (+30.0 pts gap) |
| 2023 | Epping Forest | 18 | 5 | 27.8% | Conservative Party · 48.3% of votes → 77.8% of seats (+29.5 pts gap) |
| 2023 | St Albans | 18 | 5 | 27.8% | Liberal Democrats · 50.3% of votes → 83.3% of seats (+33.0 pts gap) |
| 2019 | Coventry | 18 | 5 | 27.8% | Labour Party · 45.7% of votes → 77.8% of seats (+32.1 pts gap) |
| 2018 | Gosport | 18 | 5 | 27.8% | Liberal Democrats · 23.8% of votes → 50.0% of seats (+26.2 pts gap) |
| 2018 | Reigate and Banstead | 18 | 5 | 27.8% | Conservative Party · 50.3% of votes → 77.8% of seats (+27.5 pts gap) |
| 2018 | South Tyneside | 18 | 5 | 27.8% | Labour Party · 57.3% of votes → 94.4% of seats (+37.1 pts gap) |
| 2026 | Wokingham | 19 | 5 | 26.3% | Liberal Democrats · 34.8% of votes → 63.2% of seats (+28.4 pts gap) |
| 2018 | Tameside | 19 | 5 | 26.3% | Labour Party · 53.8% of votes → 89.5% of seats (+35.7 pts gap) |
| 2016 | Wokingham | 19 | 5 | 26.3% | Conservative Party · 47.7% of votes → 78.9% of seats (+31.3 pts gap) |
| 2026 | Oldham | 20 | 5 | 25.0% | Reform UK · 37.2% of votes → 65.0% of seats (+27.8 pts gap) |
| 2022 | Epping Forest | 20 | 5 | 25.0% | RES · 17.3% of votes → 30.0% of seats (+12.7 pts gap) |
| 2022 | Wolverhampton | 20 | 5 | 25.0% | Labour Party · 57.3% of votes → 85.0% of seats (+27.7 pts gap) |
| 2019 | Rochdale | 20 | 5 | 25.0% | Labour Party · 49.4% of votes → 80.0% of seats (+30.6 pts gap) |
| 2018 | Salford | 20 | 5 | 25.0% | Labour Party · 53.3% of votes → 85.0% of seats (+31.7 pts gap) |
| 2016 | North Tyneside | 20 | 5 | 25.0% | Labour Party · 53.6% of votes → 85.0% of seats (+31.4 pts gap) |
| 2024 | Bolton | 21 | 5 | 23.8% | HandBFI · 7.5% of votes → 14.3% of seats (+6.7 pts gap) |
| 2024 | Salford | 21 | 5 | 23.8% | Labour Party · 58.3% of votes → 85.7% of seats (+27.4 pts gap) |
| 2024 | Stockport | 21 | 5 | 23.8% | Liberal Democrats · 34.2% of votes → 52.4% of seats (+18.2 pts gap) |
| 2023 | Salford | 21 | 5 | 23.8% | Labour Party · 56.8% of votes → 85.7% of seats (+28.9 pts gap) |
| 2023 | North Tyneside | 21 | 5 | 23.8% | Labour Party · 55.5% of votes → 85.7% of seats (+30.3 pts gap) |
| 2022 | Stockport | 21 | 5 | 23.8% | Liberal Democrats · 34.7% of votes → 47.6% of seats (+13.0 pts gap) |
| 2022 | Barnsley | 21 | 5 | 23.8% | Labour Party · 46.2% of votes → 76.2% of seats (+30.0 pts gap) |
| 2019 | Barnsley | 21 | 5 | 23.8% | Labour Party · 34.9% of votes → 57.1% of seats (+22.2 pts gap) |
| 2019 | Trafford | 21 | 5 | 23.8% | Labour Party · 41.3% of votes → 66.7% of seats (+25.4 pts gap) |
| 2019 | Wakefield | 21 | 5 | 23.8% | Labour Party · 42.5% of votes → 66.7% of seats (+24.2 pts gap) |
| 2018 | Barnsley | 21 | 5 | 23.8% | Labour Party · 58.0% of votes → 90.5% of seats (+32.5 pts gap) |
| 2016 | Stockport | 21 | 5 | 23.8% | Liberal Democrats · 29.2% of votes → 42.9% of seats (+13.6 pts gap) |
| 2023 | Sefton | 22 | 5 | 22.7% | Labour Party · 51.8% of votes → 81.8% of seats (+30.0 pts gap) |
| 2022 | Trafford | 22 | 5 | 22.7% | Labour Party · 45.1% of votes → 68.2% of seats (+23.0 pts gap) |
| 2022 | Gateshead | 22 | 5 | 22.7% | Labour Party · 49.9% of votes → 77.3% of seats (+27.4 pts gap) |
| 2019 | Wolverhampton | 22 | 5 | 22.7% | Labour Party · 47.4% of votes → 72.7% of seats (+25.4 pts gap) |
| 2024 | Peterborough | 23 | 5 | 21.7% | PETE FIRST · 15.6% of votes → 34.8% of seats (+19.2 pts gap) |
| 2019 | Dudley | 24 | 5 | 20.8% | Conservative Party · 39.7% of votes → 54.2% of seats (+14.5 pts gap) |
| 2024 | Wigan | 25 | 5 | 20.0% | Labour Party · 51.7% of votes → 84.0% of seats (+32.3 pts gap) |
| 2023 | Sunderland | 25 | 5 | 20.0% | Labour Party · 45.3% of votes → 68.0% of seats (+22.7 pts gap) |
| 2022 | Sunderland | 25 | 5 | 20.0% | Labour Party · 44.5% of votes → 64.0% of seats (+19.5 pts gap) |
| 2018 | Sunderland | 25 | 5 | 20.0% | Labour Party · 47.0% of votes → 68.0% of seats (+21.0 pts gap) |
| 2016 | Dudley | 25 | 5 | 20.0% | Labour Party · 38.5% of votes → 56.0% of seats (+17.5 pts gap) |
| 2021 | Wigan | 26 | 5 | 19.2% | Labour Party · 49.8% of votes → 73.1% of seats (+23.3 pts gap) |
| 2023 | Newcastle Upon Tyne | 27 | 5 | 18.5% | Labour Party · 41.7% of votes → 51.9% of seats (+10.1 pts gap) |
| 2019 | Ryedale | 27 | 5 | 18.5% | Independent · 28.3% of votes → 40.7% of seats (+12.5 pts gap) |
| 2019 | West Devon | 27 | 5 | 18.5% | Independent · 30.7% of votes → 40.7% of seats (+10.0 pts gap) |
| 2023 | East Cambridgeshire | 28 | 5 | 17.9% | Conservative Party · 38.4% of votes → 53.6% of seats (+15.1 pts gap) |
| 2023 | Sheffield | 29 | 5 | 17.2% | Liberal Democrats · 25.9% of votes → 37.9% of seats (+12.0 pts gap) |
| 2021 | Sheffield | 29 | 5 | 17.2% | Liberal Democrats · 20.9% of votes → 31.0% of seats (+10.2 pts gap) |
| 2026 | Sheffield | 30 | 5 | 16.7% | Reform UK · 26.4% of votes → 40.0% of seats (+13.6 pts gap) |
| 2023 | Folkestone & Hythe | 30 | 5 | 16.7% | Labour Party · 20.9% of votes → 33.3% of seats (+12.4 pts gap) |
| 2023 | Boston | 30 | 5 | 16.7% | BOST IND · 45.3% of votes → 60.0% of seats (+14.7 pts gap) |
| 2022 | Bradford | 30 | 5 | 16.7% | Labour Party · 43.1% of votes → 63.3% of seats (+20.3 pts gap) |
| 2019 | Bradford | 30 | 5 | 16.7% | Labour Party · 45.5% of votes → 60.0% of seats (+14.5 pts gap) |
| 2016 | Bradford | 30 | 5 | 16.7% | Labour Party · 39.9% of votes → 50.0% of seats (+10.1 pts gap) |
| 2023 | South Hams | 31 | 5 | 16.1% | Liberal Democrats · 43.2% of votes → 61.3% of seats (+18.1 pts gap) |
| 2023 | Malvern Hills | 31 | 5 | 16.1% | Independent · 25.7% of votes → 35.5% of seats (+9.8 pts gap) |
| 2019 | South Hams | 31 | 5 | 16.1% | Conservative Party · 38.1% of votes → 51.6% of seats (+13.5 pts gap) |
| 2023 | Dover | 32 | 5 | 15.6% | Labour Party · 40.7% of votes → 53.1% of seats (+12.4 pts gap) |
| 2019 | Babergh | 32 | 5 | 15.6% | Conservative Party · 34.8% of votes → 46.9% of seats (+12.0 pts gap) |
| 2016 | Liverpool | 32 | 5 | 15.6% | Labour Party · 58.8% of votes → 84.4% of seats (+25.5 pts gap) |
| 2023 | Mid Suffolk | 34 | 5 | 14.7% | Green Party · 56.8% of votes → 70.6% of seats (+13.8 pts gap) |
| 2019 | Hinckley and Bosworth | 34 | 5 | 14.7% | Liberal Democrats · 46.4% of votes → 61.8% of seats (+15.3 pts gap) |
| 2019 | Torridge | 34 | 5 | 14.7% | Independent · 35.2% of votes → 50.0% of seats (+14.8 pts gap) |
| 2019 | Stratford-on-Avon | 36 | 5 | 13.9% | Conservative Party · 45.8% of votes → 55.6% of seats (+9.7 pts gap) |
| 2019 | East Staffordshire | 37 | 5 | 13.5% | Conservative Party · 48.1% of votes → 62.2% of seats (+14.1 pts gap) |
| 2019 | Forest of Dean | 38 | 5 | 13.2% | Independent · 25.6% of votes → 39.5% of seats (+13.8 pts gap) |
| 2019 | North West Leicestershire | 38 | 5 | 13.2% | Conservative Party · 45.1% of votes → 52.6% of seats (+7.6 pts gap) |
| 2024 | Brentwood | 39 | 5 | 12.8% | Conservative Party · 39.4% of votes → 48.7% of seats (+9.3 pts gap) |
| 2024 | Gloucester | 39 | 5 | 12.8% | Liberal Democrats · 32.8% of votes → 43.6% of seats (+10.8 pts gap) |
| 2023 | Spelthorne | 39 | 5 | 12.8% | Liberal Democrats · 18.6% of votes → 25.6% of seats (+7.1 pts gap) |
| 2023 | Newark & Sherwood | 39 | 5 | 12.8% | Independent · 17.9% of votes → 28.2% of seats (+10.3 pts gap) |
| 2016 | Gloucester | 39 | 5 | 12.8% | Conservative Party · 44.6% of votes → 56.4% of seats (+11.9 pts gap) |
| 2016 | Rochford | 39 | 5 | 12.8% | Conservative Party · 46.1% of votes → 53.8% of seats (+7.7 pts gap) |
| 2019 | Mid Devon | 41 | 5 | 12.2% | Independent · 12.6% of votes → 24.4% of seats (+11.8 pts gap) |
| 2023 | East Lindsey | 42 | 5 | 11.9% | Independent · 26.2% of votes → 33.3% of seats (+7.2 pts gap) |
| 2019 | Blackpool | 42 | 5 | 11.9% | Labour Party · 43.9% of votes → 54.8% of seats (+10.9 pts gap) |
| 2019 | Gravesham | 44 | 5 | 11.4% | Labour Party · 40.3% of votes → 54.5% of seats (+14.3 pts gap) |
| 2022 | Monmouthshire | 46 | 5 | 10.9% | Labour Party · 36.1% of votes → 47.8% of seats (+11.7 pts gap) |
| 2019 | Middlesbrough | 46 | 5 | 10.9% | Labour Party · 34.9% of votes → 43.5% of seats (+8.6 pts gap) |
| 2019 | Scarborough | 46 | 5 | 10.9% | Conservative Party · 25.9% of votes → 34.8% of seats (+8.9 pts gap) |
| 2017 | Vale of Glamorgan | 47 | 5 | 10.6% | Conservative Party · 41.8% of votes → 48.9% of seats (+7.2 pts gap) |
| 2016 | Welwyn Hatfield | 48 | 5 | 10.4% | Conservative Party · 47.6% of votes → 58.3% of seats (+10.8 pts gap) |
| 2024 | Maidstone | 49 | 5 | 10.2% | Liberal Democrats · 19.5% of votes → 24.5% of seats (+4.9 pts gap) |
| 2023 | Derby | 51 | 5 | 9.8% | Independent · 3.4% of votes → 5.9% of seats (+2.5 pts gap) |
| 2018 | Blackburn with Darwen | 51 | 5 | 9.8% | Labour Party · 59.8% of votes → 72.5% of seats (+12.8 pts gap) |
| 2023 | South Kesteven | 52 | 5 | 9.6% | Conservative Party · 31.3% of votes → 38.5% of seats (+7.1 pts gap) |
| 2023 | North East Derbyshire | 53 | 5 | 9.4% | Labour Party · 43.1% of votes → 52.8% of seats (+9.8 pts gap) |
| 2024 | Wokingham | 54 | 5 | 9.3% | Liberal Democrats · 41.3% of votes → 50.0% of seats (+8.7 pts gap) |
| 2023 | Sevenoaks | 54 | 5 | 9.3% | Conservative Party · 51.1% of votes → 61.1% of seats (+10.1 pts gap) |
| 2023 | Arun | 54 | 5 | 9.3% | Liberal Democrats · 21.1% of votes → 25.9% of seats (+4.8 pts gap) |
| 2017 | Bridgend | 54 | 5 | 9.3% | Labour Party · 38.6% of votes → 48.1% of seats (+9.6 pts gap) |
| 2022 | Harrow | 55 | 5 | 9.1% | Conservative Party · 47.1% of votes → 56.4% of seats (+9.3 pts gap) |
| 2022 | Havering | 55 | 5 | 9.1% | Conservative Party · 31.9% of votes → 41.8% of seats (+9.9 pts gap) |
| 2019 | Staffordshire Moorlands | 56 | 5 | 8.9% | Conservative Party · 36.2% of votes → 44.6% of seats (+8.4 pts gap) |
| 2022 | Neath Port Talbot | 57 | 5 | 8.8% | Independent · 23.8% of votes → 31.6% of seats (+7.8 pts gap) |
| 2018 | Kingston upon Hull | 57 | 5 | 8.8% | Liberal Democrats · 36.4% of votes → 42.1% of seats (+5.7 pts gap) |
| 2023 | Redcar & Cleveland | 59 | 5 | 8.5% | Labour Party · 31.6% of votes → 39.0% of seats (+7.4 pts gap) |
| 2019 | Redcar and Cleveland | 59 | 5 | 8.5% | Independent · 19.1% of votes → 23.7% of seats (+4.6 pts gap) |
| 2023 | East Devon | 60 | 5 | 8.3% | Independent · 25.7% of votes → 31.7% of seats (+5.9 pts gap) |
| 2023 | Oldham | 60 | 5 | 8.3% | Labour Party · 45.9% of votes → 53.3% of seats (+7.4 pts gap) |
| 2022 | Powys | 61 | 5 | 8.2% | Liberal Democrats · 28.3% of votes → 37.7% of seats (+9.4 pts gap) |
| 2018 | Harrow | 63 | 5 | 7.9% | Labour Party · 46.6% of votes → 55.6% of seats (+8.9 pts gap) |
| 2022 | Flintshire | 65 | 5 | 7.7% | Labour Party · 40.3% of votes → 49.2% of seats (+8.9 pts gap) |
| 2017 | Carmarthenshire | 70 | 5 | 7.1% | Plaid Cymru · 38.6% of votes → 47.1% of seats (+8.6 pts gap) |
| 2022 | Carmarthenshire | 74 | 5 | 6.8% | Plaid Cymru · 42.5% of votes → 51.4% of seats (+8.8 pts gap) |
| 2022 | Swansea | 75 | 5 | 6.7% | Labour Party · 55.4% of votes → 60.0% of seats (+4.6 pts gap) |
| 2017 | Cumbria | 84 | 5 | 6.0% | Labour Party · 26.3% of votes → 31.0% of seats (+4.7 pts gap) |
| 2026 | Redditch | 9 | 4 | 44.4% | Reform UK · 39.2% of votes → 88.9% of seats (+49.7 pts gap) |
| 2026 | Tamworth | 9 | 4 | 44.4% | Reform UK · 51.8% of votes → 100.0% of seats (+48.2 pts gap) |
| 2019 | Redditch | 10 | 4 | 40.0% | Conservative Party · 40.5% of votes → 90.0% of seats (+49.5 pts gap) |
| 2026 | Harlow | 11 | 4 | 36.4% | Conservative Party · 56.7% of votes → 100.0% of seats (+43.3 pts gap) |
| 2026 | Hyndburn | 11 | 4 | 36.4% | Reform UK · 41.9% of votes → 72.7% of seats (+30.8 pts gap) |
| 2024 | Woking | 11 | 4 | 36.4% | Liberal Democrats · 53.7% of votes → 90.9% of seats (+37.2 pts gap) |
| 2023 | Hart | 11 | 4 | 36.4% | CCH · 17.4% of votes → 36.4% of seats (+18.9 pts gap) |
| 2026 | Havant | 12 | 4 | 33.3% | Reform UK · 41.6% of votes → 75.0% of seats (+33.4 pts gap) |
| 2024 | Crawley | 12 | 4 | 33.3% | Labour Party · 46.8% of votes → 83.3% of seats (+36.5 pts gap) |
| 2024 | Eastleigh | 12 | 4 | 33.3% | Liberal Democrats · 47.7% of votes → 83.3% of seats (+35.6 pts gap) |
| 2024 | Hartlepool | 12 | 4 | 33.3% | Labour Party · 46.5% of votes → 75.0% of seats (+28.5 pts gap) |
| 2024 | Hyndburn | 12 | 4 | 33.3% | Labour Party · 47.7% of votes → 83.3% of seats (+35.6 pts gap) |
| 2016 | Hyndburn | 12 | 4 | 33.3% | Labour Party · 51.1% of votes → 83.3% of seats (+32.2 pts gap) |
| 2016 | Rossendale | 12 | 4 | 33.3% | Labour Party · 47.1% of votes → 83.3% of seats (+36.2 pts gap) |
| 2026 | Three Rivers | 13 | 4 | 30.8% | Conservative Party · 31.6% of votes → 53.8% of seats (+22.2 pts gap) |
| 2026 | Worthing | 13 | 4 | 30.8% | Green Party · 23.7% of votes → 46.2% of seats (+22.5 pts gap) |
| 2024 | Rochford | 13 | 4 | 30.8% | Independent · 17.0% of votes → 30.8% of seats (+13.7 pts gap) |
| 2023 | Eastleigh | 13 | 4 | 30.8% | Liberal Democrats · 51.9% of votes → 92.3% of seats (+40.4 pts gap) |
| 2021 | Harlow | 13 | 4 | 30.8% | Conservative Party · 60.0% of votes → 92.3% of seats (+32.3 pts gap) |
| 2021 | Cannock Chase | 13 | 4 | 30.8% | Conservative Party · 52.6% of votes → 92.3% of seats (+39.7 pts gap) |
| 2019 | Stevenage | 13 | 4 | 30.8% | Labour Party · 38.4% of votes → 69.2% of seats (+30.9 pts gap) |
| 2016 | Cannock Chase | 13 | 4 | 30.8% | Labour Party · 36.9% of votes → 69.2% of seats (+32.3 pts gap) |
| 2016 | Stevenage | 13 | 4 | 30.8% | Labour Party · 42.8% of votes → 76.9% of seats (+34.2 pts gap) |
| 2026 | Adur | 14 | 4 | 28.6% | Reform UK · 29.3% of votes → 42.9% of seats (+13.6 pts gap) |
| 2026 | Basildon | 14 | 4 | 28.6% | Reform UK · 40.8% of votes → 78.6% of seats (+37.7 pts gap) |
| 2026 | Gosport | 14 | 4 | 28.6% | Reform UK · 34.3% of votes → 64.3% of seats (+30.0 pts gap) |
| 2026 | Norwich | 14 | 4 | 28.6% | Green Party · 44.0% of votes → 78.6% of seats (+34.6 pts gap) |
| 2026 | Stevenage | 14 | 4 | 28.6% | Reform UK · 35.2% of votes → 64.3% of seats (+29.1 pts gap) |
| 2024 | Chorley | 14 | 4 | 28.6% | Labour Party · 60.5% of votes → 92.9% of seats (+32.4 pts gap) |
| 2024 | Winchester | 14 | 4 | 28.6% | Liberal Democrats · 47.7% of votes → 78.6% of seats (+30.8 pts gap) |
| 2023 | Portsmouth | 14 | 4 | 28.6% | Liberal Democrats · 29.1% of votes → 50.0% of seats (+20.9 pts gap) |
| 2023 | Chorley | 14 | 4 | 28.6% | Labour Party · 59.3% of votes → 92.9% of seats (+33.6 pts gap) |
| 2022 | Castle Point | 14 | 4 | 28.6% | People's Independent Party · 28.6% of votes → 42.9% of seats (+14.3 pts gap) |
| 2022 | Tandridge | 14 | 4 | 28.6% | Liberal Democrats · 21.1% of votes → 35.7% of seats (+14.6 pts gap) |
| 2021 | Exeter | 14 | 4 | 28.6% | Labour Party · 44.4% of votes → 78.6% of seats (+34.2 pts gap) |
| 2021 | North East Lincolnshire | 14 | 4 | 28.6% | Conservative Party · 55.9% of votes → 85.7% of seats (+29.8 pts gap) |
| 2019 | Exeter | 14 | 4 | 28.6% | Labour Party · 36.5% of votes → 64.3% of seats (+27.8 pts gap) |
| 2018 | Rochford | 14 | 4 | 28.6% | Conservative Party · 48.8% of votes → 85.7% of seats (+36.9 pts gap) |
| 2016 | Havant | 14 | 4 | 28.6% | Conservative Party · 46.9% of votes → 78.6% of seats (+31.6 pts gap) |
| 2016 | Portsmouth | 14 | 4 | 28.6% | Liberal Democrats · 29.3% of votes → 57.1% of seats (+27.8 pts gap) |
| 2026 | West Lancashire | 15 | 4 | 26.7% | Reform UK · 32.0% of votes → 46.7% of seats (+14.6 pts gap) |
| 2021 | Castle Point | 15 | 4 | 26.7% | CI IND · 16.7% of votes → 33.3% of seats (+16.6 pts gap) |
| 2021 | Fareham | 15 | 4 | 26.7% | Conservative Party · 56.2% of votes → 86.7% of seats (+30.5 pts gap) |
| 2019 | Chorley | 15 | 4 | 26.7% | Labour Party · 52.6% of votes → 86.7% of seats (+34.1 pts gap) |
| 2016 | Amber Valley | 15 | 4 | 26.7% | Labour Party · 40.6% of votes → 73.3% of seats (+32.7 pts gap) |
| 2024 | Reading | 16 | 4 | 25.0% | Labour Party · 46.4% of votes → 75.0% of seats (+28.6 pts gap) |
| 2024 | Reigate and Banstead | 16 | 4 | 25.0% | Green Party · 23.8% of votes → 31.3% of seats (+7.5 pts gap) |
| 2023 | Cambridge | 16 | 4 | 25.0% | Labour Party · 38.2% of votes → 62.5% of seats (+24.3 pts gap) |
| 2023 | Winchester | 16 | 4 | 25.0% | Liberal Democrats · 50.1% of votes → 81.3% of seats (+31.2 pts gap) |
| 2023 | Tunbridge Wells | 16 | 4 | 25.0% | Tunbridge Wells Alliance · 18.1% of votes → 31.3% of seats (+13.2 pts gap) |
| 2022 | Cambridge | 16 | 4 | 25.0% | Labour Party · 44.5% of votes → 75.0% of seats (+30.5 pts gap) |
| 2021 | Amber Valley | 16 | 4 | 25.0% | Conservative Party · 53.6% of votes → 81.3% of seats (+27.7 pts gap) |
| 2021 | Southampton | 16 | 4 | 25.0% | Conservative Party · 42.9% of votes → 68.8% of seats (+25.9 pts gap) |
| 2021 | Elmbridge | 16 | 4 | 25.0% | RES · 17.1% of votes → 31.3% of seats (+14.2 pts gap) |
| 2019 | Elmbridge | 16 | 4 | 25.0% | Molesey · 7.1% of votes → 12.5% of seats (+5.4 pts gap) |
| 2019 | Ipswich | 16 | 4 | 25.0% | Labour Party · 39.8% of votes → 68.8% of seats (+28.9 pts gap) |
| 2019 | South Lakeland | 16 | 4 | 25.0% | Liberal Democrats · 45.0% of votes → 75.0% of seats (+30.0 pts gap) |
| 2019 | Southampton | 16 | 4 | 25.0% | Labour Party · 36.7% of votes → 56.3% of seats (+19.5 pts gap) |
| 2018 | Fareham | 16 | 4 | 25.0% | Conservative Party · 54.3% of votes → 75.0% of seats (+20.7 pts gap) |
| 2018 | Runnymede | 16 | 4 | 25.0% | Conservative Party · 48.7% of votes → 68.8% of seats (+20.1 pts gap) |
| 2018 | St Helens | 16 | 4 | 25.0% | Labour Party · 49.7% of votes → 81.3% of seats (+31.5 pts gap) |
| 2016 | Reading | 16 | 4 | 25.0% | Labour Party · 44.9% of votes → 68.8% of seats (+23.8 pts gap) |
| 2026 | Hastings | 17 | 4 | 23.5% | Green Party · 41.7% of votes → 58.8% of seats (+17.1 pts gap) |
| 2026 | Welwyn Hatfield | 17 | 4 | 23.5% | Liberal Democrats · 19.8% of votes → 35.3% of seats (+15.5 pts gap) |
| 2024 | Bury | 17 | 4 | 23.5% | Labour Party · 45.9% of votes → 70.6% of seats (+24.7 pts gap) |
| 2024 | Calderdale | 17 | 4 | 23.5% | Labour Party · 41.6% of votes → 58.8% of seats (+17.2 pts gap) |
| 2024 | Southampton | 17 | 4 | 23.5% | Labour Party · 40.3% of votes → 70.6% of seats (+30.3 pts gap) |
| 2024 | Thurrock | 17 | 4 | 23.5% | Labour Party · 52.2% of votes → 70.6% of seats (+18.4 pts gap) |
| 2022 | Exeter | 17 | 4 | 23.5% | Labour Party · 45.8% of votes → 70.6% of seats (+24.8 pts gap) |
| 2022 | Southampton | 17 | 4 | 23.5% | Labour Party · 46.7% of votes → 76.5% of seats (+29.7 pts gap) |
| 2021 | Nuneaton & Bedworth | 17 | 4 | 23.5% | Conservative Party · 58.2% of votes → 88.2% of seats (+30.0 pts gap) |
| 2018 | Cherwell | 17 | 4 | 23.5% | Conservative Party · 49.5% of votes → 70.6% of seats (+21.1 pts gap) |
| 2016 | Ipswich | 17 | 4 | 23.5% | Labour Party · 46.1% of votes → 76.5% of seats (+30.4 pts gap) |
| 2016 | St Helens | 17 | 4 | 23.5% | Labour Party · 57.9% of votes → 88.2% of seats (+30.4 pts gap) |
| 2016 | West Oxfordshire | 17 | 4 | 23.5% | Conservative Party · 45.9% of votes → 70.6% of seats (+24.7 pts gap) |
| 2026 | Cherwell | 18 | 4 | 22.2% | Liberal Democrats · 24.7% of votes → 44.4% of seats (+19.8 pts gap) |
| 2026 | Epping Forest | 18 | 4 | 22.2% | Reform UK · 40.7% of votes → 61.1% of seats (+20.4 pts gap) |
| 2024 | Coventry | 18 | 4 | 22.2% | Labour Party · 49.8% of votes → 83.3% of seats (+33.5 pts gap) |
| 2024 | Halton | 18 | 4 | 22.2% | Labour Party · 68.1% of votes → 94.4% of seats (+26.3 pts gap) |
| 2024 | South Tyneside | 18 | 4 | 22.2% | Independent · 31.9% of votes → 55.6% of seats (+23.7 pts gap) |
| 2019 | Maidstone | 18 | 4 | 22.2% | Conservative Party · 39.6% of votes → 50.0% of seats (+10.4 pts gap) |
| 2018 | Halton | 18 | 4 | 22.2% | Labour Party · 66.7% of votes → 94.4% of seats (+27.8 pts gap) |
| 2016 | Huntingdonshire | 18 | 4 | 22.2% | Independent · 14.6% of votes → 27.8% of seats (+13.2 pts gap) |
| 2016 | Nuneaton and Bedworth | 18 | 4 | 22.2% | Labour Party · 40.3% of votes → 66.7% of seats (+26.3 pts gap) |
| 2016 | Southampton | 18 | 4 | 22.2% | Labour Party · 41.7% of votes → 66.7% of seats (+24.9 pts gap) |
| 2026 | Basingstoke and Deane | 19 | 4 | 21.1% | Basingstoke & Deane Independents · 12.7% of votes → 26.3% of seats (+13.6 pts gap) |
| 2026 | Kingston upon Hull | 19 | 4 | 21.1% | Reform UK · 35.7% of votes → 52.6% of seats (+17.0 pts gap) |
| 2024 | Tameside | 19 | 4 | 21.1% | Labour Party · 52.1% of votes → 73.7% of seats (+21.6 pts gap) |
| 2022 | Milton Keynes | 19 | 4 | 21.1% | Labour Party · 36.5% of votes → 47.4% of seats (+10.9 pts gap) |
| 2022 | Tameside | 19 | 4 | 21.1% | Labour Party · 54.6% of votes → 78.9% of seats (+24.4 pts gap) |
| 2022 | South Tyneside | 19 | 4 | 21.1% | Labour Party · 48.6% of votes → 73.7% of seats (+25.1 pts gap) |
| 2021 | Kingston Upon Hull | 19 | 4 | 21.1% | Liberal Democrats · 38.9% of votes → 52.6% of seats (+13.8 pts gap) |
| 2019 | Halton | 19 | 4 | 21.1% | Labour Party · 60.5% of votes → 89.5% of seats (+28.9 pts gap) |
| 2019 | Swindon | 19 | 4 | 21.1% | Conservative Party · 39.6% of votes → 63.2% of seats (+23.5 pts gap) |
| 2016 | Maidstone | 19 | 4 | 21.1% | Liberal Democrats · 26.6% of votes → 42.1% of seats (+15.5 pts gap) |
| 2016 | South Cambridgeshire | 19 | 4 | 21.1% | Conservative Party · 38.1% of votes → 52.6% of seats (+14.5 pts gap) |
| 2026 | North Tyneside | 20 | 4 | 20.0% | Reform UK · 31.1% of votes → 50.0% of seats (+18.9 pts gap) |
| 2024 | Rochdale | 20 | 4 | 20.0% | Labour Party · 42.1% of votes → 70.0% of seats (+27.9 pts gap) |
| 2024 | Swindon | 20 | 4 | 20.0% | Labour Party · 48.6% of votes → 70.0% of seats (+21.4 pts gap) |
| 2024 | Walsall | 20 | 4 | 20.0% | Conservative Party · 37.1% of votes → 60.0% of seats (+22.9 pts gap) |
| 2024 | Wolverhampton | 20 | 4 | 20.0% | Labour Party · 56.1% of votes → 80.0% of seats (+23.9 pts gap) |
| 2023 | Rochdale | 20 | 4 | 20.0% | Labour Party · 53.2% of votes → 80.0% of seats (+26.8 pts gap) |
| 2022 | Salford | 20 | 4 | 20.0% | Labour Party · 53.7% of votes → 75.0% of seats (+21.3 pts gap) |
| 2019 | Walsall | 20 | 4 | 20.0% | Conservative Party · 41.0% of votes → 65.0% of seats (+24.0 pts gap) |
| 2018 | Rochdale | 20 | 4 | 20.0% | Labour Party · 52.1% of votes → 80.0% of seats (+27.9 pts gap) |
| 2016 | Newcastle-under-Lyme | 20 | 4 | 20.0% | Labour Party · 37.9% of votes → 55.0% of seats (+17.1 pts gap) |
| 2016 | Oldham | 20 | 4 | 20.0% | Labour Party · 49.1% of votes → 75.0% of seats (+25.9 pts gap) |
| 2016 | Rochdale | 20 | 4 | 20.0% | Labour Party · 51.9% of votes → 80.0% of seats (+28.1 pts gap) |
| 2026 | Wolverhampton | 21 | 4 | 19.0% | Reform UK · 34.2% of votes → 57.1% of seats (+22.9 pts gap) |
| 2023 | Barnsley | 21 | 4 | 19.0% | Labour Party · 46.1% of votes → 71.4% of seats (+25.3 pts gap) |
| 2022 | Sefton | 21 | 4 | 19.0% | Labour Party · 49.3% of votes → 76.2% of seats (+26.9 pts gap) |
| 2022 | Walsall | 21 | 4 | 19.0% | Conservative Party · 43.7% of votes → 61.9% of seats (+18.2 pts gap) |
| 2021 | Swindon | 21 | 4 | 19.0% | Conservative Party · 48.5% of votes → 71.4% of seats (+22.9 pts gap) |
| 2019 | St Albans | 21 | 4 | 19.0% | Liberal Democrats · 42.4% of votes → 57.1% of seats (+14.8 pts gap) |
| 2019 | Stockport | 21 | 4 | 19.0% | Liberal Democrats · 34.6% of votes → 47.6% of seats (+13.0 pts gap) |
| 2018 | Epping Forest | 21 | 4 | 19.0% | Loughton · 19.9% of votes → 33.3% of seats (+13.4 pts gap) |
| 2018 | Wakefield | 21 | 4 | 19.0% | Labour Party · 51.7% of votes → 76.2% of seats (+24.5 pts gap) |
| 2016 | Barnsley | 21 | 4 | 19.0% | Labour Party · 56.3% of votes → 85.7% of seats (+29.4 pts gap) |
| 2024 | Gateshead | 22 | 4 | 18.2% | Labour Party · 49.9% of votes → 72.7% of seats (+22.8 pts gap) |
| 2023 | Gateshead | 22 | 4 | 18.2% | Labour Party · 50.2% of votes → 68.2% of seats (+18.0 pts gap) |
| 2021 | Epping Forest | 22 | 4 | 18.2% | RES · 18.5% of votes → 31.8% of seats (+13.3 pts gap) |
| 2018 | Oldham | 22 | 4 | 18.2% | Labour Party · 55.7% of votes → 81.8% of seats (+26.1 pts gap) |
| 2016 | Gateshead | 22 | 4 | 18.2% | Labour Party · 51.5% of votes → 77.3% of seats (+25.7 pts gap) |
| 2022 | Kirklees | 23 | 4 | 17.4% | Labour Party · 40.9% of votes → 60.9% of seats (+19.9 pts gap) |
| 2019 | Kirklees | 23 | 4 | 17.4% | Labour Party · 36.7% of votes → 47.8% of seats (+11.1 pts gap) |
| 2018 | Sefton | 23 | 4 | 17.4% | Labour Party · 51.9% of votes → 73.9% of seats (+22.0 pts gap) |
| 2026 | Oxford | 24 | 4 | 16.7% | Labour Party · 28.9% of votes → 41.7% of seats (+12.7 pts gap) |
| 2023 | Kirklees | 24 | 4 | 16.7% | Labour Party · 42.6% of votes → 58.3% of seats (+15.7 pts gap) |
| 2022 | Oxford | 24 | 4 | 16.7% | Labour Party · 43.9% of votes → 62.5% of seats (+18.6 pts gap) |
| 2023 | Rutland | 25 | 4 | 16.0% | Labour Party · 3.1% of votes → 8.0% of seats (+4.9 pts gap) |
| 2021 | Trafford | 25 | 4 | 16.0% | Labour Party · 45.5% of votes → 64.0% of seats (+18.5 pts gap) |
| 2018 | Wigan | 25 | 4 | 16.0% | Labour Party · 52.3% of votes → 72.0% of seats (+19.7 pts gap) |
| 2019 | Sunderland | 26 | 4 | 15.4% | Labour Party · 32.7% of votes → 46.2% of seats (+13.5 pts gap) |
| 2024 | Newcastle Upon Tyne | 27 | 4 | 14.8% | Labour Party · 40.6% of votes → 55.6% of seats (+15.0 pts gap) |
| 2023 | Eastbourne | 27 | 4 | 14.8% | Liberal Democrats · 49.7% of votes → 70.4% of seats (+20.6 pts gap) |
| 2019 | Eastbourne | 27 | 4 | 14.8% | Liberal Democrats · 49.6% of votes → 66.7% of seats (+17.0 pts gap) |
| 2019 | Fenland | 27 | 4 | 14.8% | Independent · 23.1% of votes → 37.0% of seats (+13.9 pts gap) |
| 2022 | Gosport | 28 | 4 | 14.3% | Liberal Democrats · 41.0% of votes → 57.1% of seats (+16.1 pts gap) |
| 2021 | Sunderland | 28 | 4 | 14.3% | Labour Party · 40.1% of votes → 53.6% of seats (+13.5 pts gap) |
| 2019 | East Cambridgeshire | 28 | 4 | 14.3% | Conservative Party · 41.9% of votes → 53.6% of seats (+11.7 pts gap) |
| 2024 | Sheffield | 29 | 4 | 13.8% | Labour Party · 39.8% of votes → 51.7% of seats (+11.9 pts gap) |
| 2024 | Bradford | 30 | 4 | 13.3% | Independent · 20.3% of votes → 30.0% of seats (+9.7 pts gap) |
| 2019 | Boston | 30 | 4 | 13.3% | Conservative Party · 45.0% of votes → 53.3% of seats (+8.4 pts gap) |
| 2018 | Bradford | 30 | 4 | 13.3% | Labour Party · 51.9% of votes → 66.7% of seats (+14.8 pts gap) |
| 2016 | Woking | 30 | 4 | 13.3% | Conservative Party · 47.4% of votes → 56.7% of seats (+9.3 pts gap) |
| 2019 | Copeland | 31 | 4 | 12.9% | Labour Party · 49.1% of votes → 61.3% of seats (+12.2 pts gap) |
| 2018 | Liverpool | 31 | 4 | 12.9% | Labour Party · 64.0% of votes → 80.6% of seats (+16.6 pts gap) |
| 2023 | Babergh | 32 | 4 | 12.5% | Independent · 15.9% of votes → 28.1% of seats (+12.2 pts gap) |
| 2022 | Blaenau Gwent | 33 | 4 | 12.1% | Labour Party · 49.9% of votes → 63.6% of seats (+13.7 pts gap) |
| 2022 | Ceredigion | 33 | 4 | 12.1% | Plaid Cymru · 47.2% of votes → 57.6% of seats (+10.4 pts gap) |
| 2023 | Blaby | 34 | 4 | 11.8% | Conservative Party · 42.0% of votes → 55.9% of seats (+13.8 pts gap) |
| 2023 | Hinckley & Bosworth | 34 | 4 | 11.8% | Liberal Democrats · 48.0% of votes → 64.7% of seats (+16.7 pts gap) |
| 2019 | Bolsover | 35 | 4 | 11.4% | Independent · 35.0% of votes → 45.7% of seats (+10.7 pts gap) |
| 2019 | Eden | 35 | 4 | 11.4% | Independent · 16.9% of votes → 28.6% of seats (+11.6 pts gap) |
| 2024 | Cannock Chase | 36 | 4 | 11.1% | Labour Party · 44.5% of votes → 58.3% of seats (+13.8 pts gap) |
| 2024 | Havant | 36 | 4 | 11.1% | Labour Party · 18.4% of votes → 27.8% of seats (+9.4 pts gap) |
| 2023 | Torridge | 36 | 4 | 11.1% | Independent · 33.3% of votes → 44.4% of seats (+11.2 pts gap) |
| 2023 | Torbay | 36 | 4 | 11.1% | Conservative Party · 44.1% of votes → 52.8% of seats (+8.7 pts gap) |
| 2023 | Ribble Valley | 36 | 4 | 11.1% | Liberal Democrats · 15.6% of votes → 22.2% of seats (+6.6 pts gap) |
| 2019 | South Oxfordshire | 36 | 4 | 11.1% | Liberal Democrats · 25.0% of votes → 33.3% of seats (+8.3 pts gap) |
| 2023 | Fylde | 37 | 4 | 10.8% | Conservative Party · 44.6% of votes → 51.4% of seats (+6.7 pts gap) |
| 2023 | North Kesteven | 37 | 4 | 10.8% | Conservative Party · 46.5% of votes → 56.8% of seats (+10.2 pts gap) |
| 2023 | South Holland | 37 | 4 | 10.8% | SH IND · 29.5% of votes → 40.5% of seats (+11.0 pts gap) |
| 2023 | East Staffordshire | 37 | 4 | 10.8% | Labour Party · 45.1% of votes → 56.8% of seats (+11.6 pts gap) |
| 2023 | North West Leicestershire | 38 | 4 | 10.5% | Labour Party · 37.7% of votes → 44.7% of seats (+7.0 pts gap) |
| 2019 | Carlisle | 39 | 4 | 10.3% | Labour Party · 29.5% of votes → 38.5% of seats (+9.0 pts gap) |
| 2022 | Gwynedd | 41 | 4 | 9.8% | Plaid Cymru · 50.6% of votes → 61.0% of seats (+10.4 pts gap) |
| 2023 | Dartford | 42 | 4 | 9.5% | Conservative Party · 55.8% of votes → 69.0% of seats (+13.2 pts gap) |
| 2023 | East Hampshire | 43 | 4 | 9.3% | W & B COMM · 7.3% of votes → 14.0% of seats (+6.6 pts gap) |
| 2023 | North Lincolnshire | 43 | 4 | 9.3% | Conservative Party · 51.4% of votes → 62.8% of seats (+11.4 pts gap) |
| 2017 | Monmouthshire | 43 | 4 | 9.3% | Conservative Party · 46.4% of votes → 58.1% of seats (+11.7 pts gap) |
| 2023 | Luton | 45 | 4 | 8.9% | Labour Party · 50.2% of votes → 60.0% of seats (+9.8 pts gap) |
| 2023 | Middlesbrough | 46 | 4 | 8.7% | Labour Party · 46.5% of votes → 54.3% of seats (+7.8 pts gap) |
| 2019 | Erewash | 47 | 4 | 8.5% | Conservative Party · 49.8% of votes → 57.4% of seats (+7.7 pts gap) |
| 2023 | Mid Sussex | 48 | 4 | 8.3% | Liberal Democrats · 36.9% of votes → 41.7% of seats (+4.8 pts gap) |
| 2022 | St. Helens | 48 | 4 | 8.3% | Labour Party · 52.5% of votes → 60.4% of seats (+7.9 pts gap) |
| 2022 | Wrexham | 48 | 4 | 8.3% | Labour Party · 23.5% of votes → 29.2% of seats (+5.7 pts gap) |
| 2016 | Elmbridge | 48 | 4 | 8.3% | Molesey · 9.6% of votes → 12.5% of seats (+2.9 pts gap) |
| 2019 | Darlington | 50 | 4 | 8.0% | Labour Party · 33.2% of votes → 40.0% of seats (+6.8 pts gap) |
| 2019 | South Ribble | 50 | 4 | 8.0% | Labour Party · 34.4% of votes → 44.0% of seats (+9.6 pts gap) |
| 2016 | Stroud | 51 | 4 | 7.8% | Conservative Party · 39.9% of votes → 45.1% of seats (+5.2 pts gap) |
| 2022 | Hillingdon | 53 | 4 | 7.5% | Conservative Party · 48.2% of votes → 56.6% of seats (+8.4 pts gap) |
| 2019 | Brighton and Hove | 54 | 4 | 7.4% | Conservative Party · 22.0% of votes → 25.9% of seats (+3.9 pts gap) |
| 2019 | Waverley | 55 | 4 | 7.3% | Farnham · 19.6% of votes → 27.3% of seats (+7.6 pts gap) |
| 2017 | Powys | 56 | 4 | 7.1% | Independent · 30.8% of votes → 37.5% of seats (+6.7 pts gap) |
| 2021 | Redditch | 9 | 3 | 33.3% | Conservative Party · 56.2% of votes → 100.0% of seats (+43.8 pts gap) |
| 2016 | Redditch | 9 | 3 | 33.3% | Labour Party · 39.6% of votes → 77.8% of seats (+38.2 pts gap) |
| 2026 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 39.6% of votes → 70.0% of seats (+30.4 pts gap) |
| 2026 | Pendle | 10 | 3 | 30.0% | Independent · 17.9% of votes → 40.0% of seats (+22.1 pts gap) |
| 2024 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 50.5% of votes → 90.0% of seats (+39.5 pts gap) |
| 2024 | Tamworth | 10 | 3 | 30.0% | Labour Party · 49.4% of votes → 90.0% of seats (+40.6 pts gap) |
| 2023 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 50.3% of votes → 90.0% of seats (+39.7 pts gap) |
| 2023 | Tamworth | 10 | 3 | 30.0% | Labour Party · 43.9% of votes → 80.0% of seats (+36.1 pts gap) |
| 2022 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 52.4% of votes → 90.0% of seats (+37.6 pts gap) |
| 2022 | Woking | 10 | 3 | 30.0% | Liberal Democrats · 47.3% of votes → 70.0% of seats (+22.7 pts gap) |
| 2021 | Tamworth | 10 | 3 | 30.0% | Conservative Party · 56.9% of votes → 100.0% of seats (+43.1 pts gap) |
| 2019 | Tamworth | 10 | 3 | 30.0% | Conservative Party · 42.4% of votes → 80.0% of seats (+37.6 pts gap) |
| 2018 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 59.5% of votes → 90.0% of seats (+30.5 pts gap) |
| 2016 | Broxbourne | 10 | 3 | 30.0% | Conservative Party · 54.6% of votes → 90.0% of seats (+35.4 pts gap) |
| 2023 | Worcester | 11 | 3 | 27.3% | Green Party · 28.8% of votes → 45.5% of seats (+16.7 pts gap) |
| 2019 | Broxbourne | 11 | 3 | 27.3% | Conservative Party · 57.5% of votes → 90.9% of seats (+33.4 pts gap) |
| 2019 | Worcester | 11 | 3 | 27.3% | Conservative Party · 36.9% of votes → 63.6% of seats (+26.7 pts gap) |
| 2016 | Wyre Forest | 11 | 3 | 27.3% | Conservative Party · 29.0% of votes → 45.5% of seats (+16.5 pts gap) |
| 2023 | Hartlepool | 12 | 3 | 25.0% | Labour Party · 44.6% of votes → 75.0% of seats (+30.4 pts gap) |
| 2023 | Watford | 12 | 3 | 25.0% | Liberal Democrats · 48.8% of votes → 75.0% of seats (+26.2 pts gap) |
| 2023 | Rossendale | 12 | 3 | 25.0% | Labour Party · 44.5% of votes → 66.7% of seats (+22.2 pts gap) |
| 2023 | Worthing | 12 | 3 | 25.0% | Labour Party · 46.8% of votes → 75.0% of seats (+28.2 pts gap) |
| 2022 | Watford | 12 | 3 | 25.0% | Liberal Democrats · 51.3% of votes → 83.3% of seats (+32.0 pts gap) |
| 2022 | Rossendale | 12 | 3 | 25.0% | Labour Party · 40.7% of votes → 58.3% of seats (+17.6 pts gap) |
| 2018 | Watford | 12 | 3 | 25.0% | Liberal Democrats · 43.7% of votes → 75.0% of seats (+31.3 pts gap) |
| 2016 | North East Lincolnshire | 12 | 3 | 25.0% | Labour Party · 35.7% of votes → 58.3% of seats (+22.7 pts gap) |
| 2024 | Worthing | 13 | 3 | 23.1% | Labour Party · 45.1% of votes → 69.2% of seats (+24.1 pts gap) |
| 2023 | Stevenage | 13 | 3 | 23.1% | Labour Party · 44.1% of votes → 69.2% of seats (+25.1 pts gap) |
| 2022 | Rochford | 13 | 3 | 23.1% | RES · 21.0% of votes → 30.8% of seats (+9.7 pts gap) |
| 2021 | Watford | 13 | 3 | 23.1% | Liberal Democrats · 43.9% of votes → 69.2% of seats (+25.3 pts gap) |
| 2021 | Norwich | 13 | 3 | 23.1% | Labour Party · 41.6% of votes → 61.5% of seats (+20.0 pts gap) |
| 2021 | Runnymede | 13 | 3 | 23.1% | Conservative Party · 45.0% of votes → 69.2% of seats (+24.2 pts gap) |
| 2019 | Watford | 13 | 3 | 23.1% | Liberal Democrats · 55.2% of votes → 76.9% of seats (+21.7 pts gap) |
| 2018 | Daventry | 13 | 3 | 23.1% | Conservative Party · 54.0% of votes → 84.6% of seats (+30.6 pts gap) |
| 2018 | Exeter | 13 | 3 | 23.1% | Labour Party · 47.3% of votes → 76.9% of seats (+29.7 pts gap) |
| 2018 | Three Rivers | 13 | 3 | 23.1% | Liberal Democrats · 37.4% of votes → 61.5% of seats (+24.2 pts gap) |
| 2016 | Rushmoor | 13 | 3 | 23.1% | Conservative Party · 39.1% of votes → 61.5% of seats (+22.4 pts gap) |
| 2016 | Weymouth and Portland | 13 | 3 | 23.1% | Labour Party · 34.3% of votes → 53.8% of seats (+19.5 pts gap) |
| 2024 | Cambridge | 14 | 3 | 21.4% | Labour Party · 40.9% of votes → 64.3% of seats (+23.4 pts gap) |
| 2024 | Portsmouth | 14 | 3 | 21.4% | Liberal Democrats · 26.7% of votes → 50.0% of seats (+23.3 pts gap) |
| 2024 | Runnymede | 14 | 3 | 21.4% | Labour Party · 21.8% of votes → 28.6% of seats (+6.7 pts gap) |
| 2023 | Runnymede | 14 | 3 | 21.4% | Independent · 6.3% of votes → 14.3% of seats (+8.0 pts gap) |
| 2023 | Tandridge | 14 | 3 | 21.4% | Independent · 23.5% of votes → 42.9% of seats (+19.3 pts gap) |
| 2022 | Slough | 14 | 3 | 21.4% | Labour Party · 57.7% of votes → 85.7% of seats (+28.0 pts gap) |
| 2022 | Basildon | 14 | 3 | 21.4% | Conservative Party · 49.0% of votes → 71.4% of seats (+22.4 pts gap) |
| 2022 | Worthing | 14 | 3 | 21.4% | Labour Party · 48.1% of votes → 71.4% of seats (+23.3 pts gap) |
| 2021 | Slough | 14 | 3 | 21.4% | Labour Party · 57.6% of votes → 78.6% of seats (+21.0 pts gap) |
| 2021 | Portsmouth | 14 | 3 | 21.4% | Liberal Democrats · 27.1% of votes → 42.9% of seats (+15.8 pts gap) |
| 2021 | Rushmoor | 14 | 3 | 21.4% | Conservative Party · 52.7% of votes → 78.6% of seats (+25.9 pts gap) |
| 2019 | Basildon | 14 | 3 | 21.4% | Labour Party · 24.4% of votes → 42.9% of seats (+18.4 pts gap) |
| 2019 | Castle Point | 14 | 3 | 21.4% | Canvey Island Independent Party · 24.1% of votes → 42.9% of seats (+18.8 pts gap) |
| 2019 | Mole Valley | 14 | 3 | 21.4% | Liberal Democrats · 50.4% of votes → 78.6% of seats (+28.2 pts gap) |
| 2019 | Slough | 14 | 3 | 21.4% | Labour Party · 59.0% of votes → 85.7% of seats (+26.7 pts gap) |
| 2018 | Adur | 14 | 3 | 21.4% | Conservative Party · 44.0% of votes → 64.3% of seats (+20.3 pts gap) |
| 2018 | Castle Point | 14 | 3 | 21.4% | Canvey Island Independent Party · 22.2% of votes → 35.7% of seats (+13.6 pts gap) |
| 2018 | Slough | 14 | 3 | 21.4% | Labour Party · 66.0% of votes → 92.9% of seats (+26.8 pts gap) |
| 2018 | Tandridge | 14 | 3 | 21.4% | Liberal Democrats · 20.1% of votes → 28.6% of seats (+8.4 pts gap) |
| 2016 | Cambridge | 14 | 3 | 21.4% | Labour Party · 45.9% of votes → 64.3% of seats (+18.4 pts gap) |
| 2016 | Mole Valley | 14 | 3 | 21.4% | Ashtead · 17.5% of votes → 28.6% of seats (+11.1 pts gap) |
| 2016 | Slough | 14 | 3 | 21.4% | Labour Party · 61.0% of votes → 85.7% of seats (+24.7 pts gap) |
| 2016 | Tandridge | 14 | 3 | 21.4% | Liberal Democrats · 22.3% of votes → 35.7% of seats (+13.4 pts gap) |
| 2026 | Rugby | 15 | 3 | 20.0% | Liberal Democrats · 20.1% of votes → 40.0% of seats (+19.9 pts gap) |
| 2023 | Reigate & Banstead | 15 | 3 | 20.0% | Conservative Party · 37.8% of votes → 46.7% of seats (+8.9 pts gap) |
| 2022 | Reigate and Banstead | 15 | 3 | 20.0% | Conservative Party · 36.6% of votes → 53.3% of seats (+16.8 pts gap) |
| 2021 | Rugby | 15 | 3 | 20.0% | Conservative Party · 48.6% of votes → 66.7% of seats (+18.1 pts gap) |
| 2019 | Amber Valley | 15 | 3 | 20.0% | Conservative Party · 38.0% of votes → 53.3% of seats (+15.3 pts gap) |
| 2018 | Basildon | 15 | 3 | 20.0% | Conservative Party · 51.2% of votes → 66.7% of seats (+15.5 pts gap) |
| 2018 | Cambridge | 15 | 3 | 20.0% | Labour Party · 46.4% of votes → 66.7% of seats (+20.3 pts gap) |
| 2018 | Havant | 15 | 3 | 20.0% | Conservative Party · 62.3% of votes → 86.7% of seats (+24.4 pts gap) |
| 2018 | Winchester | 15 | 3 | 20.0% | Liberal Democrats · 41.2% of votes → 60.0% of seats (+18.8 pts gap) |
| 2026 | Knowsley | 16 | 3 | 18.8% | Independent · 11.4% of votes → 25.0% of seats (+13.6 pts gap) |
| 2026 | West Oxfordshire | 16 | 3 | 18.8% | Conservative Party · 30.4% of votes → 43.8% of seats (+13.4 pts gap) |
| 2024 | Cherwell | 16 | 3 | 18.8% | Liberal Democrats · 28.3% of votes → 50.0% of seats (+21.7 pts gap) |
| 2024 | Preston | 16 | 3 | 18.8% | Labour Party · 42.2% of votes → 56.3% of seats (+14.1 pts gap) |
| 2024 | Welwyn Hatfield | 16 | 3 | 18.8% | Labour Party · 31.8% of votes → 50.0% of seats (+18.2 pts gap) |
| 2023 | North Hertfordshire | 16 | 3 | 18.8% | Liberal Democrats · 32.4% of votes → 50.0% of seats (+17.6 pts gap) |
| 2023 | Welwyn Hatfield | 16 | 3 | 18.8% | Liberal Democrats · 25.9% of votes → 37.5% of seats (+11.6 pts gap) |
| 2023 | Cherwell | 16 | 3 | 18.8% | Labour Party · 25.7% of votes → 31.3% of seats (+5.5 pts gap) |
| 2022 | Tunbridge Wells | 16 | 3 | 18.8% | Liberal Democrats · 22.4% of votes → 37.5% of seats (+15.1 pts gap) |
| 2022 | Elmbridge | 16 | 3 | 18.8% | RES · 15.1% of votes → 25.0% of seats (+9.9 pts gap) |
| 2021 | Cherwell | 16 | 3 | 18.8% | Conservative Party · 47.7% of votes → 68.8% of seats (+21.1 pts gap) |
| 2019 | Cambridge | 16 | 3 | 18.8% | Labour Party · 37.2% of votes → 56.3% of seats (+19.1 pts gap) |
| 2019 | St Helens | 16 | 3 | 18.8% | Labour Party · 36.6% of votes → 62.5% of seats (+25.9 pts gap) |
| 2019 | Winchester | 16 | 3 | 18.8% | Liberal Democrats · 48.3% of votes → 68.8% of seats (+20.5 pts gap) |
| 2018 | Ipswich | 16 | 3 | 18.8% | Labour Party · 48.4% of votes → 75.0% of seats (+26.6 pts gap) |
| 2016 | Fareham | 16 | 3 | 18.8% | Conservative Party · 52.3% of votes → 75.0% of seats (+22.7 pts gap) |
| 2026 | Reading | 17 | 3 | 17.6% | Labour Party · 29.2% of votes → 41.2% of seats (+12.0 pts gap) |
| 2026 | Southend-on-Sea | 17 | 3 | 17.6% | Reform UK · 31.3% of votes → 47.1% of seats (+15.8 pts gap) |
| 2023 | Bury | 17 | 3 | 17.6% | Labour Party · 47.8% of votes → 64.7% of seats (+16.9 pts gap) |
| 2023 | Solihull | 17 | 3 | 17.6% | Conservative Party · 45.2% of votes → 58.8% of seats (+13.7 pts gap) |
| 2022 | Welwyn Hatfield | 17 | 3 | 17.6% | Liberal Democrats · 29.6% of votes → 41.2% of seats (+11.6 pts gap) |
| 2022 | Nuneaton and Bedworth | 17 | 3 | 17.6% | Conservative Party · 50.5% of votes → 70.6% of seats (+20.1 pts gap) |
| 2022 | Solihull | 17 | 3 | 17.6% | Conservative Party · 46.3% of votes → 52.9% of seats (+6.6 pts gap) |
| 2021 | Reading | 17 | 3 | 17.6% | Labour Party · 40.5% of votes → 58.8% of seats (+18.4 pts gap) |
| 2021 | Thurrock | 17 | 3 | 17.6% | Conservative Party · 53.2% of votes → 76.5% of seats (+23.3 pts gap) |
| 2019 | Bury | 17 | 3 | 17.6% | Labour Party · 38.9% of votes → 52.9% of seats (+14.1 pts gap) |
| 2019 | Calderdale | 17 | 3 | 17.6% | Labour Party · 37.8% of votes → 58.8% of seats (+21.0 pts gap) |
| 2018 | Colchester | 17 | 3 | 17.6% | Conservative Party · 40.4% of votes → 58.8% of seats (+18.4 pts gap) |
| 2018 | Solihull | 17 | 3 | 17.6% | Green Party · 21.4% of votes → 29.4% of seats (+8.0 pts gap) |
| 2016 | Carlisle | 17 | 3 | 17.6% | Independent · 4.3% of votes → 11.8% of seats (+7.4 pts gap) |
| 2016 | Southend-on-Sea | 17 | 3 | 17.6% | Conservative Party · 29.7% of votes → 47.1% of seats (+17.3 pts gap) |
| 2026 | Peterborough | 18 | 3 | 16.7% | Conservative Party · 23.3% of votes → 33.3% of seats (+10.0 pts gap) |
| 2024 | Basingstoke and Deane | 18 | 3 | 16.7% | B and D IND · 12.3% of votes → 22.2% of seats (+9.9 pts gap) |
| 2023 | Wokingham | 18 | 3 | 16.7% | Liberal Democrats · 41.5% of votes → 61.1% of seats (+19.6 pts gap) |
| 2023 | Maidstone | 18 | 3 | 16.7% | Independent · 11.3% of votes → 22.2% of seats (+10.9 pts gap) |
| 2023 | South Tyneside | 18 | 3 | 16.7% | Labour Party · 44.1% of votes → 61.1% of seats (+17.0 pts gap) |
| 2023 | Coventry | 18 | 3 | 16.7% | Labour Party · 50.4% of votes → 72.2% of seats (+21.9 pts gap) |
| 2022 | Halton | 18 | 3 | 16.7% | Labour Party · 64.2% of votes → 88.9% of seats (+24.7 pts gap) |
| 2022 | Southend-on-Sea | 18 | 3 | 16.7% | Labour Party · 30.4% of votes → 44.4% of seats (+14.1 pts gap) |
| 2022 | North Hertfordshire | 18 | 3 | 16.7% | Labour Party · 30.8% of votes → 50.0% of seats (+19.2 pts gap) |
| 2022 | Coventry | 18 | 3 | 16.7% | Labour Party · 47.9% of votes → 72.2% of seats (+24.4 pts gap) |
| 2021 | Wokingham | 18 | 3 | 16.7% | Conservative Party · 46.2% of votes → 66.7% of seats (+20.5 pts gap) |
| 2021 | Tunbridge Wells | 18 | 3 | 16.7% | Liberal Democrats · 27.6% of votes → 38.9% of seats (+11.3 pts gap) |
| 2021 | Reigate & Banstead | 18 | 3 | 16.7% | Conservative Party · 47.1% of votes → 61.1% of seats (+14.0 pts gap) |
| 2021 | Solihull | 18 | 3 | 16.7% | Conservative Party · 53.8% of votes → 66.7% of seats (+12.9 pts gap) |
| 2021 | Adur | 18 | 3 | 16.7% | Conservative Party · 45.4% of votes → 61.1% of seats (+15.7 pts gap) |
| 2018 | Reading | 18 | 3 | 16.7% | Labour Party · 48.3% of votes → 66.7% of seats (+18.4 pts gap) |
| 2018 | Wokingham | 18 | 3 | 16.7% | Conservative Party · 45.3% of votes → 61.1% of seats (+15.8 pts gap) |
| 2016 | Coventry | 18 | 3 | 16.7% | Labour Party · 49.0% of votes → 72.2% of seats (+23.2 pts gap) |
| 2024 | Milton Keynes | 19 | 3 | 15.8% | Liberal Democrats · 19.1% of votes → 31.6% of seats (+12.4 pts gap) |
| 2022 | Swindon | 19 | 3 | 15.8% | Labour Party · 46.0% of votes → 63.2% of seats (+17.1 pts gap) |
| 2021 | Plymouth | 19 | 3 | 15.8% | Conservative Party · 50.6% of votes → 73.7% of seats (+23.1 pts gap) |
| 2021 | Southend On Sea | 19 | 3 | 15.8% | Conservative Party · 40.5% of votes → 57.9% of seats (+17.4 pts gap) |
| 2021 | Maidstone | 19 | 3 | 15.8% | Conservative Party · 47.3% of votes → 63.2% of seats (+15.8 pts gap) |
| 2021 | Coventry | 19 | 3 | 15.8% | Labour Party · 43.6% of votes → 68.4% of seats (+24.8 pts gap) |
| 2019 | Plymouth | 19 | 3 | 15.8% | Labour Party · 37.4% of votes → 52.6% of seats (+15.2 pts gap) |
| 2016 | Halton | 19 | 3 | 15.8% | Labour Party · 67.8% of votes → 89.5% of seats (+21.6 pts gap) |
| 2016 | Plymouth | 19 | 3 | 15.8% | Labour Party · 36.5% of votes → 57.9% of seats (+21.4 pts gap) |
| 2026 | Bolton | 20 | 3 | 15.0% | Reform UK · 32.6% of votes → 45.0% of seats (+12.4 pts gap) |
| 2023 | Walsall | 20 | 3 | 15.0% | Conservative Party · 44.5% of votes → 65.0% of seats (+20.5 pts gap) |
| 2021 | St Albans | 20 | 3 | 15.0% | Liberal Democrats · 41.2% of votes → 55.0% of seats (+13.8 pts gap) |
| 2018 | Basingstoke and Deane | 20 | 3 | 15.0% | Labour Party · 31.3% of votes → 45.0% of seats (+13.7 pts gap) |
| 2018 | Milton Keynes | 20 | 3 | 15.0% | Liberal Democrats · 19.2% of votes → 30.0% of seats (+10.8 pts gap) |
| 2018 | Preston | 20 | 3 | 15.0% | Labour Party · 48.6% of votes → 65.0% of seats (+16.4 pts gap) |
| 2018 | St Albans | 20 | 3 | 15.0% | Liberal Democrats · 34.9% of votes → 45.0% of seats (+10.1 pts gap) |
| 2016 | Basingstoke and Deane | 20 | 3 | 15.0% | Labour Party · 27.8% of votes → 40.0% of seats (+12.2 pts gap) |
| 2016 | Bolton | 20 | 3 | 15.0% | Labour Party · 40.2% of votes → 60.0% of seats (+19.8 pts gap) |
| 2016 | Kingston upon Hull | 20 | 3 | 15.0% | Liberal Democrats · 34.7% of votes → 45.0% of seats (+10.3 pts gap) |
| 2016 | Milton Keynes | 20 | 3 | 15.0% | Labour Party · 36.3% of votes → 50.0% of seats (+13.7 pts gap) |
| 2016 | Walsall | 20 | 3 | 15.0% | Labour Party · 43.2% of votes → 50.0% of seats (+6.8 pts gap) |
| 2026 | Trafford | 21 | 3 | 14.3% | Labour Party · 23.3% of votes → 38.1% of seats (+14.8 pts gap) |
| 2023 | Peterborough | 21 | 3 | 14.3% | Liberal Democrats · 11.5% of votes → 19.0% of seats (+7.5 pts gap) |
| 2021 | Bolton | 21 | 3 | 14.3% | Conservative Party · 38.8% of votes → 47.6% of seats (+8.9 pts gap) |
| 2021 | Stockport | 21 | 3 | 14.3% | Labour Party · 32.0% of votes → 38.1% of seats (+6.1 pts gap) |
| 2018 | Stockport | 21 | 3 | 14.3% | Labour Party · 33.4% of votes → 42.9% of seats (+9.5 pts gap) |
| 2018 | Walsall | 21 | 3 | 14.3% | Conservative Party · 47.8% of votes → 61.9% of seats (+14.2 pts gap) |
| 2016 | Epping Forest | 21 | 3 | 14.3% | Loughton · 26.5% of votes → 38.1% of seats (+11.6 pts gap) |
| 2024 | Sefton | 22 | 3 | 13.6% | Labour Party · 54.2% of votes → 77.3% of seats (+23.0 pts gap) |
| 2021 | Wolverhampton | 22 | 3 | 13.6% | Labour Party · 47.3% of votes → 63.6% of seats (+16.4 pts gap) |
| 2021 | Wakefield | 22 | 3 | 13.6% | Labour Party · 45.2% of votes → 59.1% of seats (+13.9 pts gap) |
| 2019 | Melton | 23 | 3 | 13.0% | Conservative Party · 59.7% of votes → 78.3% of seats (+18.5 pts gap) |
| 2016 | Kirklees | 23 | 3 | 13.0% | Labour Party · 39.8% of votes → 52.2% of seats (+12.4 pts gap) |
| 2021 | Kirklees | 25 | 3 | 12.0% | Labour Party · 35.5% of votes → 48.0% of seats (+12.5 pts gap) |
| 2021 | Sandwell | 27 | 3 | 11.1% | Labour Party · 53.1% of votes → 66.7% of seats (+13.6 pts gap) |
| 2019 | Folkestone and Hythe | 30 | 3 | 10.0% | Conservative Party · 36.4% of votes → 43.3% of seats (+6.9 pts gap) |
| 2017 | Isle of Anglesey | 30 | 3 | 10.0% | Independent · 36.8% of votes → 43.3% of seats (+6.6 pts gap) |
| 2019 | Selby | 31 | 3 | 9.7% | Conservative Party · 47.7% of votes → 51.6% of seats (+3.9 pts gap) |
| 2019 | West Lindsey | 32 | 3 | 9.4% | Liberal Democrats · 31.3% of votes → 37.5% of seats (+6.2 pts gap) |
| 2024 | Harlow | 33 | 3 | 9.1% | Conservative Party · 43.8% of votes → 51.5% of seats (+7.7 pts gap) |
| 2023 | Harborough | 34 | 3 | 8.8% | Conservative Party · 34.1% of votes → 44.1% of seats (+10.0 pts gap) |
| 2019 | Cotswold | 34 | 3 | 8.8% | Liberal Democrats · 41.4% of votes → 52.9% of seats (+11.6 pts gap) |
| 2019 | Malvern Hills | 34 | 3 | 8.8% | Independent · 22.2% of votes → 29.4% of seats (+7.2 pts gap) |
| 2026 | Leeds | 36 | 3 | 8.3% | Conservative Party · 16.1% of votes → 19.4% of seats (+3.3 pts gap) |
| 2021 | Hartlepool | 36 | 3 | 8.3% | Conservative Party · 25.5% of votes → 36.1% of seats (+10.6 pts gap) |
| 2019 | Chichester | 36 | 3 | 8.3% | Conservative Party · 42.0% of votes → 50.0% of seats (+8.0 pts gap) |
| 2019 | Rother | 38 | 3 | 7.9% | Independent · 27.0% of votes → 34.2% of seats (+7.2 pts gap) |
| 2019 | Stafford | 38 | 3 | 7.9% | Independent · 14.7% of votes → 18.4% of seats (+3.7 pts gap) |
| 2023 | Canterbury | 39 | 3 | 7.7% | Labour Party · 36.6% of votes → 46.2% of seats (+9.6 pts gap) |
| 2023 | Gravesham | 39 | 3 | 7.7% | Labour Party · 46.9% of votes → 56.4% of seats (+9.6 pts gap) |
| 2019 | North Kesteven | 39 | 3 | 7.7% | Independent · 10.6% of votes → 15.4% of seats (+4.8 pts gap) |
| 2022 | Pembrokeshire | 41 | 3 | 7.3% | Independent · 44.5% of votes → 53.7% of seats (+9.1 pts gap) |
| 2019 | Test Valley | 41 | 3 | 7.3% | Conservative Party · 45.7% of votes → 53.7% of seats (+8.0 pts gap) |
| 2017 | Denbighshire | 42 | 3 | 7.1% | Plaid Cymru · 9.9% of votes → 16.7% of seats (+6.8 pts gap) |
| 2019 | North Lincolnshire | 43 | 3 | 7.0% | Conservative Party · 52.9% of votes → 62.8% of seats (+9.9 pts gap) |
| 2022 | Newcastle-under-Lyme | 44 | 3 | 6.8% | Conservative Party · 48.9% of votes → 56.8% of seats (+7.9 pts gap) |
| 2018 | Newcastle-under-Lyme | 44 | 3 | 6.8% | Labour Party · 39.7% of votes → 45.5% of seats (+5.8 pts gap) |
| 2023 | West Lancashire | 45 | 3 | 6.7% | Labour Party · 52.7% of votes → 57.8% of seats (+5.0 pts gap) |
| 2023 | Lichfield | 46 | 3 | 6.5% | Liberal Democrats · 12.2% of votes → 15.2% of seats (+3.0 pts gap) |
| 2023 | Ashford | 47 | 3 | 6.4% | ASHF IND · 15.0% of votes → 19.1% of seats (+4.2 pts gap) |
| 2017 | Wrexham | 49 | 3 | 6.1% | Independent · 41.4% of votes → 46.9% of seats (+5.6 pts gap) |
| 2023 | Wyre | 50 | 3 | 6.0% | Conservative Party · 52.8% of votes → 60.0% of seats (+7.2 pts gap) |
| 2023 | Charnwood | 52 | 3 | 5.8% | Conservative Party · 38.3% of votes → 44.2% of seats (+6.0 pts gap) |
| 2017 | Gwynedd | 54 | 3 | 5.6% | Plaid Cymru · 39.3% of votes → 44.4% of seats (+5.2 pts gap) |
| 2023 | South Gloucestershire | 61 | 3 | 4.9% | Labour Party · 24.1% of votes → 27.9% of seats (+3.7 pts gap) |
| 2021 | Northumberland | 67 | 3 | 4.5% | Conservative Party · 45.7% of votes → 50.7% of seats (+5.0 pts gap) |
| 2021 | Bristol, City Of | 70 | 3 | 4.3% | Green Party · 31.7% of votes → 34.3% of seats (+2.6 pts gap) |
| 2018 | Craven | 9 | 2 | 22.2% | Conservative Party · 46.4% of votes → 77.8% of seats (+31.4 pts gap) |
| 2023 | Woking | 10 | 2 | 20.0% | Liberal Democrats · 50.0% of votes → 80.0% of seats (+30.0 pts gap) |
| 2022 | Tamworth | 10 | 2 | 20.0% | Conservative Party · 47.5% of votes → 70.0% of seats (+22.5 pts gap) |
| 2021 | Broxbourne | 10 | 2 | 20.0% | Conservative Party · 63.8% of votes → 90.0% of seats (+26.2 pts gap) |
| 2021 | Woking | 10 | 2 | 20.0% | Liberal Democrats · 36.1% of votes → 50.0% of seats (+13.9 pts gap) |
| 2018 | Redditch | 10 | 2 | 20.0% | Conservative Party · 44.0% of votes → 70.0% of seats (+26.0 pts gap) |
| 2018 | Tamworth | 10 | 2 | 20.0% | Conservative Party · 47.8% of votes → 80.0% of seats (+32.2 pts gap) |
| 2016 | Tamworth | 10 | 2 | 20.0% | Conservative Party · 39.2% of votes → 60.0% of seats (+20.8 pts gap) |
| 2026 | Lincoln | 11 | 2 | 18.2% | Labour Party · 23.1% of votes → 36.4% of seats (+13.3 pts gap) |
| 2024 | Lincoln | 11 | 2 | 18.2% | Labour Party · 45.0% of votes → 72.7% of seats (+27.8 pts gap) |
| 2023 | Lincoln | 11 | 2 | 18.2% | Labour Party · 49.2% of votes → 72.7% of seats (+23.5 pts gap) |
| 2022 | Hart | 11 | 2 | 18.2% | CCH · 20.4% of votes → 36.4% of seats (+16.0 pts gap) |
| 2022 | Redditch | 11 | 2 | 18.2% | Labour Party · 43.0% of votes → 63.6% of seats (+20.6 pts gap) |
| 2019 | Craven | 11 | 2 | 18.2% | Independent · 28.0% of votes → 45.5% of seats (+17.5 pts gap) |
| 2019 | Harlow | 11 | 2 | 18.2% | Labour Party · 38.7% of votes → 63.6% of seats (+24.9 pts gap) |
| 2019 | Hartlepool | 11 | 2 | 18.2% | ForBritn · 3.6% of votes → 9.1% of seats (+5.5 pts gap) |
| 2019 | Worthing | 11 | 2 | 18.2% | Conservative Party · 36.5% of votes → 45.5% of seats (+8.9 pts gap) |
| 2018 | Hart | 11 | 2 | 18.2% | CC(Hart) · 20.7% of votes → 36.4% of seats (+15.6 pts gap) |
| 2018 | Wyre Forest | 11 | 2 | 18.2% | Conservative Party · 41.2% of votes → 63.6% of seats (+22.5 pts gap) |
| 2016 | Craven | 11 | 2 | 18.2% | Conservative Party · 39.6% of votes → 54.5% of seats (+15.0 pts gap) |
| 2016 | Harlow | 11 | 2 | 18.2% | Labour Party · 40.1% of votes → 63.6% of seats (+23.5 pts gap) |
| 2016 | Hartlepool | 11 | 2 | 18.2% | Labour Party · 36.3% of votes → 54.5% of seats (+18.3 pts gap) |
| 2024 | Hart | 12 | 2 | 16.7% | Liberal Democrats · 30.3% of votes → 41.7% of seats (+11.3 pts gap) |
| 2024 | North East Lincolnshire | 12 | 2 | 16.7% | Labour Party · 40.3% of votes → 50.0% of seats (+9.7 pts gap) |
| 2024 | Pendle | 12 | 2 | 16.7% | ND · 24.6% of votes → 33.3% of seats (+8.7 pts gap) |
| 2023 | Brentwood | 12 | 2 | 16.7% | Liberal Democrats · 42.6% of votes → 58.3% of seats (+15.8 pts gap) |
| 2023 | Crawley | 12 | 2 | 16.7% | Labour Party · 47.6% of votes → 66.7% of seats (+19.1 pts gap) |
| 2021 | Brentwood | 12 | 2 | 16.7% | Conservative Party · 49.1% of votes → 75.0% of seats (+25.9 pts gap) |
| 2021 | Rossendale | 12 | 2 | 16.7% | Labour Party · 45.7% of votes → 58.3% of seats (+12.7 pts gap) |
| 2019 | Hart | 12 | 2 | 16.7% | CC(Hart) · 22.9% of votes → 33.3% of seats (+10.4 pts gap) |
| 2019 | Hyndburn | 12 | 2 | 16.7% | Labour Party · 53.7% of votes → 75.0% of seats (+21.3 pts gap) |
| 2019 | Rochford | 12 | 2 | 16.7% | Conservative Party · 38.2% of votes → 58.3% of seats (+20.1 pts gap) |
| 2019 | Rossendale | 12 | 2 | 16.7% | Independent · 3.5% of votes → 8.3% of seats (+4.8 pts gap) |
| 2018 | Crawley | 12 | 2 | 16.7% | Labour Party · 47.1% of votes → 66.7% of seats (+19.6 pts gap) |
| 2016 | Worcester | 12 | 2 | 16.7% | Labour Party · 36.2% of votes → 58.3% of seats (+22.1 pts gap) |
| 2024 | Exeter | 13 | 2 | 15.4% | Labour Party · 38.1% of votes → 61.5% of seats (+23.4 pts gap) |
| 2024 | Rushmoor | 13 | 2 | 15.4% | Labour Party · 48.1% of votes → 69.2% of seats (+21.1 pts gap) |
| 2023 | Exeter | 13 | 2 | 15.4% | Labour Party · 44.0% of votes → 53.8% of seats (+9.8 pts gap) |
| 2023 | Rochford | 13 | 2 | 15.4% | Liberal Democrats · 25.0% of votes → 30.8% of seats (+5.8 pts gap) |
| 2023 | Rushmoor | 13 | 2 | 15.4% | Labour Party · 46.8% of votes → 61.5% of seats (+14.7 pts gap) |
| 2022 | Hartlepool | 13 | 2 | 15.4% | Labour Party · 40.1% of votes → 53.8% of seats (+13.7 pts gap) |
| 2022 | Rushmoor | 13 | 2 | 15.4% | Conservative Party · 45.4% of votes → 61.5% of seats (+16.1 pts gap) |
| 2022 | Stevenage | 13 | 2 | 15.4% | Labour Party · 44.7% of votes → 69.2% of seats (+24.5 pts gap) |
| 2022 | Norwich | 13 | 2 | 15.4% | Labour Party · 45.2% of votes → 61.5% of seats (+16.3 pts gap) |
| 2022 | Cannock Chase | 13 | 2 | 15.4% | Green Party · 6.1% of votes → 7.7% of seats (+1.6 pts gap) |
| 2021 | Three Rivers | 13 | 2 | 15.4% | Liberal Democrats · 38.2% of votes → 61.5% of seats (+23.3 pts gap) |
| 2019 | Rushmoor | 13 | 2 | 15.4% | Conservative Party · 41.9% of votes → 69.2% of seats (+27.3 pts gap) |
| 2018 | Brentwood | 13 | 2 | 15.4% | Conservative Party · 45.6% of votes → 61.5% of seats (+16.0 pts gap) |
| 2018 | Stevenage | 13 | 2 | 15.4% | Labour Party · 43.9% of votes → 61.5% of seats (+17.7 pts gap) |
| 2018 | Worthing | 13 | 2 | 15.4% | Conservative Party · 45.9% of votes → 61.5% of seats (+15.6 pts gap) |
| 2016 | Crawley | 13 | 2 | 15.4% | Labour Party · 45.1% of votes → 69.2% of seats (+24.1 pts gap) |
| 2026 | Brentwood | 14 | 2 | 14.3% | Reform UK · 37.0% of votes → 50.0% of seats (+13.0 pts gap) |
| 2026 | Chorley | 14 | 2 | 14.3% | Reform UK · 35.9% of votes → 50.0% of seats (+14.1 pts gap) |
| 2026 | Exeter | 14 | 2 | 14.3% | Green Party · 32.7% of votes → 42.9% of seats (+10.2 pts gap) |
| 2026 | Rushmoor | 14 | 2 | 14.3% | Reform UK · 31.3% of votes → 42.9% of seats (+11.5 pts gap) |
| 2023 | Basildon | 14 | 2 | 14.3% | Labour Party · 29.1% of votes → 42.9% of seats (+13.7 pts gap) |
| 2023 | Three Rivers | 14 | 2 | 14.3% | Liberal Democrats · 41.9% of votes → 57.1% of seats (+15.3 pts gap) |
| 2022 | Portsmouth | 14 | 2 | 14.3% | Labour Party · 31.2% of votes → 35.7% of seats (+4.5 pts gap) |
| 2022 | Three Rivers | 14 | 2 | 14.3% | Liberal Democrats · 43.5% of votes → 57.1% of seats (+13.6 pts gap) |
| 2022 | Mole Valley | 14 | 2 | 14.3% | Liberal Democrats · 45.3% of votes → 57.1% of seats (+11.8 pts gap) |
| 2022 | Runnymede | 14 | 2 | 14.3% | Independent · 11.1% of votes → 14.3% of seats (+3.2 pts gap) |
| 2022 | Adur | 14 | 2 | 14.3% | Conservative Party · 38.7% of votes → 50.0% of seats (+11.3 pts gap) |
| 2019 | Rugby | 14 | 2 | 14.3% | Conservative Party · 41.3% of votes → 57.1% of seats (+15.9 pts gap) |
| 2019 | Three Rivers | 14 | 2 | 14.3% | Liberal Democrats · 45.5% of votes → 57.1% of seats (+11.7 pts gap) |
| 2018 | Mole Valley | 14 | 2 | 14.3% | Ashtead · 12.1% of votes → 21.4% of seats (+9.4 pts gap) |
| 2018 | Rugby | 14 | 2 | 14.3% | Conservative Party · 46.9% of votes → 57.1% of seats (+10.2 pts gap) |
| 2018 | Rushmoor | 14 | 2 | 14.3% | Conservative Party · 47.3% of votes → 64.3% of seats (+17.0 pts gap) |
| 2016 | Rugby | 14 | 2 | 14.3% | Conservative Party · 36.1% of votes → 50.0% of seats (+13.9 pts gap) |
| 2026 | Cambridge | 15 | 2 | 13.3% | Green Party · 32.6% of votes → 46.7% of seats (+14.1 pts gap) |
| 2024 | Burnley | 15 | 2 | 13.3% | Labour Party · 32.4% of votes → 40.0% of seats (+7.6 pts gap) |
| 2024 | Gosport | 15 | 2 | 13.3% | Liberal Democrats · 36.7% of votes → 53.3% of seats (+16.6 pts gap) |
| 2024 | Knowsley | 15 | 2 | 13.3% | Labour Party · 63.1% of votes → 80.0% of seats (+16.9 pts gap) |
| 2023 | Burnley | 15 | 2 | 13.3% | Labour Party · 42.2% of votes → 53.3% of seats (+11.2 pts gap) |
| 2022 | Amber Valley | 15 | 2 | 13.3% | Conservative Party · 42.6% of votes → 60.0% of seats (+17.4 pts gap) |
| 2022 | Burnley | 15 | 2 | 13.3% | Liberal Democrats · 12.8% of votes → 20.0% of seats (+7.2 pts gap) |
| 2021 | Basildon | 15 | 2 | 13.3% | Conservative Party · 48.7% of votes → 66.7% of seats (+18.0 pts gap) |
| 2021 | Rochford | 15 | 2 | 13.3% | Conservative Party · 42.9% of votes → 60.0% of seats (+17.1 pts gap) |
| 2021 | Winchester | 15 | 2 | 13.3% | Liberal Democrats · 39.3% of votes → 53.3% of seats (+14.0 pts gap) |
| 2021 | North Hertfordshire | 15 | 2 | 13.3% | Conservative Party · 40.8% of votes → 53.3% of seats (+12.5 pts gap) |
| 2021 | Burnley | 15 | 2 | 13.3% | Green Party · 16.6% of votes → 20.0% of seats (+3.4 pts gap) |
| 2019 | Burnley | 15 | 2 | 13.3% | BPIP · 13.3% of votes → 20.0% of seats (+6.7 pts gap) |
| 2019 | Cannock Chase | 15 | 2 | 13.3% | Conservative Party · 36.9% of votes → 46.7% of seats (+9.8 pts gap) |
| 2019 | Knowsley | 15 | 2 | 13.3% | Labour Party · 58.5% of votes → 73.3% of seats (+14.8 pts gap) |
| 2018 | Burnley | 15 | 2 | 13.3% | Liberal Democrats · 15.3% of votes → 20.0% of seats (+4.7 pts gap) |
| 2016 | Adur | 15 | 2 | 13.3% | Conservative Party · 35.6% of votes → 46.7% of seats (+11.1 pts gap) |
| 2016 | North Hertfordshire | 15 | 2 | 13.3% | Labour Party · 27.3% of votes → 40.0% of seats (+12.7 pts gap) |
| 2016 | Three Rivers | 15 | 2 | 13.3% | Liberal Democrats · 38.9% of votes → 53.3% of seats (+14.4 pts gap) |
| 2026 | Preston | 16 | 2 | 12.5% | Liberal Democrats · 22.9% of votes → 31.3% of seats (+8.3 pts gap) |
| 2024 | Hastings | 16 | 2 | 12.5% | Green Party · 37.7% of votes → 56.3% of seats (+18.5 pts gap) |
| 2023 | Thurrock | 16 | 2 | 12.5% | Labour Party · 45.1% of votes → 56.3% of seats (+11.2 pts gap) |
| 2022 | Hastings | 16 | 2 | 12.5% | Labour Party · 42.1% of votes → 56.3% of seats (+14.2 pts gap) |
| 2022 | Thurrock | 16 | 2 | 12.5% | Conservative Party · 48.3% of votes → 56.3% of seats (+8.0 pts gap) |
| 2022 | North East Lincolnshire | 16 | 2 | 12.5% | Conservative Party · 47.3% of votes → 56.3% of seats (+9.0 pts gap) |
| 2022 | West Oxfordshire | 16 | 2 | 12.5% | Liberal Democrats · 36.0% of votes → 50.0% of seats (+14.0 pts gap) |
| 2021 | Hastings | 16 | 2 | 12.5% | Conservative Party · 39.3% of votes → 50.0% of seats (+10.7 pts gap) |
| 2021 | Preston | 16 | 2 | 12.5% | Labour Party · 42.5% of votes → 62.5% of seats (+20.0 pts gap) |
| 2019 | North East Lincolnshire | 16 | 2 | 12.5% | Conservative Party · 48.6% of votes → 62.5% of seats (+13.9 pts gap) |
| 2019 | North Hertfordshire | 16 | 2 | 12.5% | Conservative Party · 36.0% of votes → 43.8% of seats (+7.7 pts gap) |
| 2019 | Reading | 16 | 2 | 12.5% | Labour Party · 39.4% of votes → 56.3% of seats (+16.8 pts gap) |
| 2019 | West Oxfordshire | 16 | 2 | 12.5% | Conservative Party · 39.1% of votes → 50.0% of seats (+10.9 pts gap) |
| 2018 | Elmbridge | 16 | 2 | 12.5% | Conservative Party · 46.1% of votes → 62.5% of seats (+16.4 pts gap) |
| 2018 | Southampton | 16 | 2 | 12.5% | Labour Party · 42.6% of votes → 50.0% of seats (+7.4 pts gap) |
| 2018 | Thurrock | 16 | 2 | 12.5% | Labour Party · 39.8% of votes → 56.3% of seats (+16.4 pts gap) |
| 2016 | Harrogate | 16 | 2 | 12.5% | Conservative Party · 68.9% of votes → 93.8% of seats (+24.9 pts gap) |
| 2026 | Colchester | 17 | 2 | 11.8% | Conservative Party · 21.2% of votes → 29.4% of seats (+8.2 pts gap) |
| 2024 | Blackburn with Darwen | 17 | 2 | 11.8% | Independent · 34.5% of votes → 47.1% of seats (+12.6 pts gap) |
| 2024 | Solihull | 17 | 2 | 11.8% | Conservative Party · 50.5% of votes → 64.7% of seats (+14.3 pts gap) |
| 2024 | Southend-On-Sea | 17 | 2 | 11.8% | Labour Party · 31.6% of votes → 41.2% of seats (+9.6 pts gap) |
| 2024 | West Oxfordshire | 17 | 2 | 11.8% | Liberal Democrats · 30.4% of votes → 41.2% of seats (+10.8 pts gap) |
| 2023 | Reading | 17 | 2 | 11.8% | Labour Party · 47.2% of votes → 64.7% of seats (+17.5 pts gap) |
| 2023 | Southend On Sea | 17 | 2 | 11.8% | Labour Party · 28.8% of votes → 41.2% of seats (+12.4 pts gap) |
| 2023 | Blackburn with Darwen | 17 | 2 | 11.8% | Labour Party · 63.0% of votes → 82.4% of seats (+19.3 pts gap) |
| 2023 | Preston | 17 | 2 | 11.8% | Labour Party · 49.1% of votes → 64.7% of seats (+15.7 pts gap) |
| 2023 | Cannock Chase | 17 | 2 | 11.8% | Labour Party · 44.9% of votes → 52.9% of seats (+8.0 pts gap) |
| 2023 | Calderdale | 17 | 2 | 11.8% | Labour Party · 44.4% of votes → 58.8% of seats (+14.5 pts gap) |
| 2022 | Derby | 17 | 2 | 11.8% | Reform UK · 8.0% of votes → 11.8% of seats (+3.8 pts gap) |
| 2022 | Preston | 17 | 2 | 11.8% | Labour Party · 49.4% of votes → 64.7% of seats (+15.3 pts gap) |
| 2021 | Gosport | 17 | 2 | 11.8% | Conservative Party · 48.5% of votes → 64.7% of seats (+16.2 pts gap) |
| 2021 | Knowsley | 17 | 2 | 11.8% | Labour Party · 55.1% of votes → 70.6% of seats (+15.5 pts gap) |
| 2021 | West Oxfordshire | 17 | 2 | 11.8% | Conservative Party · 41.1% of votes → 52.9% of seats (+11.8 pts gap) |
| 2019 | Blackburn with Darwen | 17 | 2 | 11.8% | Labour Party · 55.3% of votes → 70.6% of seats (+15.3 pts gap) |
| 2019 | Cherwell | 17 | 2 | 11.8% | Conservative Party · 42.5% of votes → 52.9% of seats (+10.5 pts gap) |
| 2019 | Pendle | 17 | 2 | 11.8% | Liberal Democrats · 18.9% of votes → 29.4% of seats (+10.5 pts gap) |
| 2019 | Southend-on-Sea | 17 | 2 | 11.8% | Labour Party · 21.5% of votes → 29.4% of seats (+7.9 pts gap) |
| 2018 | Bury | 17 | 2 | 11.8% | Labour Party · 48.1% of votes → 64.7% of seats (+16.6 pts gap) |
| 2018 | Calderdale | 17 | 2 | 11.8% | Labour Party · 42.0% of votes → 58.8% of seats (+16.8 pts gap) |
| 2018 | Derby | 17 | 2 | 11.8% | Conservative Party · 39.9% of votes → 47.1% of seats (+7.1 pts gap) |
| 2018 | Nuneaton and Bedworth | 17 | 2 | 11.8% | Conservative Party · 51.0% of votes → 64.7% of seats (+13.7 pts gap) |
| 2018 | West Oxfordshire | 17 | 2 | 11.8% | Conservative Party · 45.4% of votes → 58.8% of seats (+13.4 pts gap) |
| 2016 | Bury | 17 | 2 | 11.8% | Labour Party · 44.1% of votes → 58.8% of seats (+14.7 pts gap) |
| 2016 | Calderdale | 17 | 2 | 11.8% | Labour Party · 38.1% of votes → 47.1% of seats (+9.0 pts gap) |
| 2016 | Derby | 17 | 2 | 11.8% | Conservative Party · 34.1% of votes → 41.2% of seats (+7.0 pts gap) |
| 2016 | Gosport | 17 | 2 | 11.8% | Liberal Democrats · 16.3% of votes → 29.4% of seats (+13.1 pts gap) |
| 2016 | Thurrock | 17 | 2 | 11.8% | Conservative Party · 28.3% of votes → 41.2% of seats (+12.9 pts gap) |
| 2023 | Basingstoke & Deane | 18 | 2 | 11.1% | B & D IND · 11.0% of votes → 16.7% of seats (+5.6 pts gap) |
| 2022 | Wokingham | 18 | 2 | 11.1% | Liberal Democrats · 40.9% of votes → 50.0% of seats (+9.1 pts gap) |
| 2022 | Blackburn with Darwen | 18 | 2 | 11.1% | Labour Party · 60.3% of votes → 77.8% of seats (+17.5 pts gap) |
| 2022 | Calderdale | 18 | 2 | 11.1% | Labour Party · 45.4% of votes → 61.1% of seats (+15.7 pts gap) |
| 2021 | Derby | 18 | 2 | 11.1% | Conservative Party · 38.5% of votes → 50.0% of seats (+11.5 pts gap) |
| 2019 | Tunbridge Wells | 18 | 2 | 11.1% | TWellsA · 17.7% of votes → 27.8% of seats (+10.1 pts gap) |
| 2019 | West Lancashire | 18 | 2 | 11.1% | Conservative Party · 33.1% of votes → 38.9% of seats (+5.8 pts gap) |
| 2019 | Wokingham | 18 | 2 | 11.1% | Conservative Party · 37.2% of votes → 44.4% of seats (+7.3 pts gap) |
| 2018 | Coventry | 18 | 2 | 11.1% | Labour Party · 52.8% of votes → 72.2% of seats (+19.4 pts gap) |
| 2018 | Peterborough | 18 | 2 | 11.1% | Liberal Democrats · 10.7% of votes → 16.7% of seats (+6.0 pts gap) |
| 2016 | St Albans | 18 | 2 | 11.1% | Liberal Democrats · 25.4% of votes → 33.3% of seats (+7.9 pts gap) |
| 2022 | Peterborough | 19 | 2 | 10.5% | Liberal Democrats · 15.2% of votes → 21.1% of seats (+5.9 pts gap) |
| 2022 | Plymouth | 19 | 2 | 10.5% | Labour Party · 43.6% of votes → 57.9% of seats (+14.3 pts gap) |
| 2022 | Kingston upon Hull, City of | 19 | 2 | 10.5% | Liberal Democrats · 45.3% of votes → 52.6% of seats (+7.3 pts gap) |
| 2019 | Kingston upon Hull | 19 | 2 | 10.5% | Labour Party · 40.1% of votes → 52.6% of seats (+12.6 pts gap) |
| 2019 | Milton Keynes | 19 | 2 | 10.5% | Conservative Party · 35.0% of votes → 42.1% of seats (+7.1 pts gap) |
| 2019 | Rutland | 19 | 2 | 10.5% | Independent · 18.1% of votes → 31.6% of seats (+13.5 pts gap) |
| 2018 | North Hertfordshire | 19 | 2 | 10.5% | Labour Party · 32.0% of votes → 42.1% of seats (+10.1 pts gap) |
| 2018 | Plymouth | 19 | 2 | 10.5% | Labour Party · 44.0% of votes → 57.9% of seats (+13.9 pts gap) |
| 2016 | Swindon | 19 | 2 | 10.5% | Labour Party · 40.2% of votes → 47.4% of seats (+7.2 pts gap) |
| 2022 | Bolton | 20 | 2 | 10.0% | Conservative Party · 34.1% of votes → 45.0% of seats (+10.9 pts gap) |
| 2021 | Oldham | 20 | 2 | 10.0% | Liberal Democrats · 10.9% of votes → 15.0% of seats (+4.1 pts gap) |
| 2019 | Basingstoke and Deane | 20 | 2 | 10.0% | Conservative Party · 46.9% of votes → 60.0% of seats (+13.1 pts gap) |
| 2019 | Bolton | 20 | 2 | 10.0% | FKF · 7.1% of votes → 10.0% of seats (+2.9 pts gap) |
| 2019 | Peterborough | 20 | 2 | 10.0% | Labour Party · 27.9% of votes → 35.0% of seats (+7.1 pts gap) |
| 2021 | Milton Keynes | 21 | 2 | 9.5% | Conservative Party · 42.0% of votes → 52.4% of seats (+10.4 pts gap) |
| 2018 | Bolton | 21 | 2 | 9.5% | Conservative Party · 34.1% of votes → 42.9% of seats (+8.8 pts gap) |
| 2021 | Walsall | 22 | 2 | 9.1% | Conservative Party · 54.1% of votes → 63.6% of seats (+9.6 pts gap) |
| 2019 | Wirral | 22 | 2 | 9.1% | Labour Party · 35.8% of votes → 45.5% of seats (+9.6 pts gap) |
| 2018 | Trafford | 22 | 2 | 9.1% | Labour Party · 45.8% of votes → 59.1% of seats (+13.3 pts gap) |
| 2016 | Blackburn with Darwen | 22 | 2 | 9.1% | Labour Party · 58.2% of votes → 63.6% of seats (+5.5 pts gap) |
| 2024 | Kirklees | 23 | 2 | 8.7% | Independent · 17.3% of votes → 26.1% of seats (+8.8 pts gap) |
| 2022 | Wirral | 23 | 2 | 8.7% | Conservative Party · 25.6% of votes → 34.8% of seats (+9.2 pts gap) |
| 2016 | Wirral | 23 | 2 | 8.7% | Labour Party · 46.9% of votes → 60.9% of seats (+13.9 pts gap) |
| 2019 | Richmondshire | 24 | 2 | 8.3% | Independent · 31.0% of votes → 41.7% of seats (+10.7 pts gap) |
| 2018 | Dudley | 24 | 2 | 8.3% | Conservative Party · 48.1% of votes → 58.3% of seats (+10.2 pts gap) |
| 2018 | Kirklees | 24 | 2 | 8.3% | Labour Party · 43.8% of votes → 50.0% of seats (+6.2 pts gap) |
| 2024 | Oxford | 25 | 2 | 8.0% | Labour Party · 38.2% of votes → 44.0% of seats (+5.8 pts gap) |
| 2023 | Dudley | 25 | 2 | 8.0% | Labour Party · 43.8% of votes → 52.0% of seats (+8.2 pts gap) |
| 2023 | Melton | 28 | 2 | 7.1% | Independent · 31.8% of votes → 35.7% of seats (+3.9 pts gap) |
| 2023 | West Devon | 30 | 2 | 6.7% | Independent · 26.0% of votes → 33.3% of seats (+7.4 pts gap) |
| 2023 | Maldon | 30 | 2 | 6.7% | MALDON IND · 20.4% of votes → 23.3% of seats (+2.9 pts gap) |
| 2022 | Merthyr Tydfil | 30 | 2 | 6.7% | Independent · 42.9% of votes → 50.0% of seats (+7.1 pts gap) |
| 2023 | Bromsgrove | 31 | 2 | 6.5% | Labour Party · 22.0% of votes → 25.8% of seats (+3.8 pts gap) |
| 2019 | Bromsgrove | 31 | 2 | 6.5% | Conservative Party · 44.2% of votes → 54.8% of seats (+10.7 pts gap) |
| 2021 | Pendle | 33 | 2 | 6.1% | Conservative Party · 48.2% of votes → 54.5% of seats (+6.3 pts gap) |
| 2021 | Bradford | 33 | 2 | 6.1% | Liberal Democrats · 7.7% of votes → 9.1% of seats (+1.4 pts gap) |
| 2017 | Merthyr Tydfil | 33 | 2 | 6.1% | Independent · 43.9% of votes → 51.5% of seats (+7.6 pts gap) |
| 2023 | Derbyshire Dales | 34 | 2 | 5.9% | Green Party · 6.1% of votes → 11.8% of seats (+5.6 pts gap) |
| 2019 | Blaby | 34 | 2 | 5.9% | Conservative Party · 50.0% of votes → 58.8% of seats (+8.8 pts gap) |
| 2019 | Mid Suffolk | 34 | 2 | 5.9% | Conservative Party · 40.7% of votes → 47.1% of seats (+6.4 pts gap) |
| 2017 | Ceredigion | 34 | 2 | 5.9% | Plaid Cymru · 36.1% of votes → 44.1% of seats (+8.0 pts gap) |
| 2023 | West Lindsey | 35 | 2 | 5.7% | Independent · 4.2% of votes → 5.7% of seats (+1.5 pts gap) |
| 2019 | Surrey Heath | 35 | 2 | 5.7% | Conservative Party · 46.5% of votes → 51.4% of seats (+4.9 pts gap) |
| 2019 | South Derbyshire | 36 | 2 | 5.6% | Conservative Party · 53.4% of votes → 61.1% of seats (+7.7 pts gap) |
| 2024 | Nuneaton and Bedworth | 38 | 2 | 5.3% | Labour Party · 45.0% of votes → 52.6% of seats (+7.6 pts gap) |
| 2019 | Bedford | 40 | 2 | 5.0% | Liberal Democrats · 30.9% of votes → 37.5% of seats (+6.6 pts gap) |
| 2023 | Slough | 42 | 2 | 4.8% | Conservative Party · 46.3% of votes → 50.0% of seats (+3.7 pts gap) |
| 2019 | Swale | 47 | 2 | 4.3% | Liberal Democrats · 9.6% of votes → 10.6% of seats (+1.0 pts gap) |
| 2017 | Pembrokeshire | 47 | 2 | 4.3% | Conservative Party · 17.5% of votes → 21.3% of seats (+3.7 pts gap) |
| 2021 | Stroud | 51 | 2 | 3.9% | Labour Party · 25.8% of votes → 29.4% of seats (+3.6 pts gap) |
| 2023 | Kings Lynn & West Norfolk | 54 | 2 | 3.7% | Independent · 29.3% of votes → 31.5% of seats (+2.2 pts gap) |
| 2019 | King's Lynn and West Norfolk | 55 | 2 | 3.6% | Conservative Party · 47.5% of votes → 50.9% of seats (+3.4 pts gap) |
| 2023 | Wirral | 66 | 2 | 3.0% | Labour Party · 40.8% of votes → 45.5% of seats (+4.6 pts gap) |
| 2019 | Kent | 2 | 1 | 50.0% | Swale · 11.8% of votes → 50.0% of seats (+38.2 pts gap) |
| 2018 | St Edmundsbury | 2 | 1 | 50.0% | Conservative Party · 51.9% of votes → 100.0% of seats (+48.1 pts gap) |
| 2017 | North Hertfordshire | 2 | 1 | 50.0% | Conservative Party · 46.0% of votes → 100.0% of seats (+54.0 pts gap) |
| 2016 | Forest Heath | 2 | 1 | 50.0% | WSuffolk · 15.7% of votes → 50.0% of seats (+34.3 pts gap) |
| 2017 | Watford | 3 | 1 | 33.3% | Labour Party · 22.3% of votes → 33.3% of seats (+11.0 pts gap) |
| 2023 | Havant | 10 | 1 | 10.0% | Conservative Party · 39.4% of votes → 50.0% of seats (+10.6 pts gap) |
| 2023 | Redditch | 10 | 1 | 10.0% | Labour Party · 43.8% of votes → 60.0% of seats (+16.2 pts gap) |
| 2018 | Woking | 10 | 1 | 10.0% | Independent · 6.2% of votes → 10.0% of seats (+3.8 pts gap) |
| 2023 | Harlow | 11 | 1 | 9.1% | Labour Party · 43.8% of votes → 54.5% of seats (+10.8 pts gap) |
| 2022 | Lincoln | 11 | 1 | 9.1% | Labour Party · 45.2% of votes → 63.6% of seats (+18.4 pts gap) |
| 2018 | Harlow | 11 | 1 | 9.1% | Labour Party · 43.4% of votes → 54.5% of seats (+11.1 pts gap) |
| 2018 | Hartlepool | 11 | 1 | 9.1% | Independent · 21.3% of votes → 27.3% of seats (+6.0 pts gap) |
| 2018 | Hyndburn | 11 | 1 | 9.1% | Labour Party · 53.2% of votes → 63.6% of seats (+10.5 pts gap) |
| 2018 | Lincoln | 11 | 1 | 9.1% | Labour Party · 47.9% of votes → 63.6% of seats (+15.8 pts gap) |
| 2016 | Hart | 11 | 1 | 9.1% | CC(Hart) · 19.0% of votes → 27.3% of seats (+8.3 pts gap) |
| 2023 | Hyndburn | 12 | 1 | 8.3% | Conservative Party · 35.6% of votes → 41.7% of seats (+6.0 pts gap) |
| 2023 | Pendle | 12 | 1 | 8.3% | Liberal Democrats · 15.9% of votes → 25.0% of seats (+9.1 pts gap) |
| 2022 | Harlow | 12 | 1 | 8.3% | Conservative Party · 48.1% of votes → 58.3% of seats (+10.2 pts gap) |
| 2022 | Pendle | 12 | 1 | 8.3% | Conservative Party · 46.4% of votes → 58.3% of seats (+12.0 pts gap) |
| 2022 | Crawley | 12 | 1 | 8.3% | Labour Party · 44.5% of votes → 58.3% of seats (+13.9 pts gap) |
| 2021 | Hart | 12 | 1 | 8.3% | CCH · 18.7% of votes → 25.0% of seats (+6.3 pts gap) |
| 2018 | Rossendale | 12 | 1 | 8.3% | CFirst · 2.7% of votes → 8.3% of seats (+5.6 pts gap) |
| 2016 | Daventry | 12 | 1 | 8.3% | Conservative Party · 49.8% of votes → 66.7% of seats (+16.9 pts gap) |
| 2024 | Norwich | 13 | 1 | 7.7% | Green Party · 32.0% of votes → 46.2% of seats (+14.2 pts gap) |
| 2024 | Three Rivers | 13 | 1 | 7.7% | Liberal Democrats · 42.3% of votes → 53.8% of seats (+11.5 pts gap) |
| 2023 | Norwich | 13 | 1 | 7.7% | Labour Party · 42.7% of votes → 53.8% of seats (+11.1 pts gap) |
| 2022 | Brentwood | 13 | 1 | 7.7% | Conservative Party · 39.5% of votes → 46.2% of seats (+6.6 pts gap) |
| 2022 | Worcester | 13 | 1 | 7.7% | Labour Party · 32.2% of votes → 46.2% of seats (+13.9 pts gap) |
| 2021 | Hyndburn | 13 | 1 | 7.7% | Conservative Party · 46.7% of votes → 53.8% of seats (+7.1 pts gap) |
| 2021 | Mole Valley | 13 | 1 | 7.7% | ASHT IND · 12.6% of votes → 23.1% of seats (+10.5 pts gap) |
| 2021 | Worthing | 13 | 1 | 7.7% | Labour Party · 34.6% of votes → 46.2% of seats (+11.5 pts gap) |
| 2018 | Cannock Chase | 13 | 1 | 7.7% | Liberal Democrats · 4.4% of votes → 7.7% of seats (+3.3 pts gap) |
| 2018 | Worcester | 13 | 1 | 7.7% | Labour Party · 34.7% of votes → 46.2% of seats (+11.4 pts gap) |
| 2016 | Brentwood | 13 | 1 | 7.7% | Independent · 6.4% of votes → 7.7% of seats (+1.3 pts gap) |
| 2024 | Rugby | 14 | 1 | 7.1% | Conservative Party · 31.9% of votes → 42.9% of seats (+10.9 pts gap) |
| 2023 | Rugby | 14 | 1 | 7.1% | Conservative Party · 36.1% of votes → 42.9% of seats (+6.8 pts gap) |
| 2021 | Crawley | 14 | 1 | 7.1% | Conservative Party · 48.6% of votes → 57.1% of seats (+8.6 pts gap) |
| 2019 | Tandridge | 14 | 1 | 7.1% | Independent · 21.0% of votes → 28.6% of seats (+7.6 pts gap) |
| 2018 | Portsmouth | 14 | 1 | 7.1% | Conservative Party · 36.7% of votes → 42.9% of seats (+6.1 pts gap) |
| 2016 | Basildon | 14 | 1 | 7.1% | Labour Party · 27.1% of votes → 35.7% of seats (+8.6 pts gap) |
| 2023 | North East Lincolnshire | 15 | 1 | 6.7% | Independent · 9.5% of votes → 13.3% of seats (+3.8 pts gap) |
| 2022 | Winchester | 15 | 1 | 6.7% | Liberal Democrats · 45.8% of votes → 60.0% of seats (+14.2 pts gap) |
| 2022 | Knowsley | 15 | 1 | 6.7% | Liberal Democrats · 4.3% of votes → 6.7% of seats (+2.3 pts gap) |
| 2018 | Amber Valley | 15 | 1 | 6.7% | Labour Party · 41.9% of votes → 53.3% of seats (+11.4 pts gap) |
| 2018 | Knowsley | 15 | 1 | 6.7% | Labour Party · 66.2% of votes → 80.0% of seats (+13.8 pts gap) |
| 2016 | Burnley | 15 | 1 | 6.7% | Labour Party · 44.3% of votes → 53.3% of seats (+9.0 pts gap) |
| 2016 | Chorley | 15 | 1 | 6.7% | Labour Party · 52.9% of votes → 66.7% of seats (+13.7 pts gap) |
| 2024 | West Lancashire | 16 | 1 | 6.3% | Conservative Party · 26.2% of votes → 31.3% of seats (+5.1 pts gap) |
| 2023 | Knowsley | 16 | 1 | 6.3% | Liberal Democrats · 7.5% of votes → 12.5% of seats (+5.0 pts gap) |
| 2023 | West Oxfordshire | 16 | 1 | 6.3% | Liberal Democrats · 27.8% of votes → 37.5% of seats (+9.7 pts gap) |
| 2021 | Tandridge | 16 | 1 | 6.3% | Conservative Party · 36.3% of votes → 43.8% of seats (+7.5 pts gap) |
| 2018 | North East Lincolnshire | 16 | 1 | 6.3% | Conservative Party · 49.5% of votes → 62.5% of seats (+13.0 pts gap) |
| 2018 | Pendle | 16 | 1 | 6.3% | Liberal Democrats · 15.1% of votes → 18.8% of seats (+3.6 pts gap) |
| 2023 | Colchester | 17 | 1 | 5.9% | Liberal Democrats · 30.3% of votes → 35.3% of seats (+5.0 pts gap) |
| 2022 | Cherwell | 17 | 1 | 5.9% | Independent · 2.6% of votes → 5.9% of seats (+3.3 pts gap) |
| 2021 | Blackburn With Darwen | 17 | 1 | 5.9% | Labour Party · 55.4% of votes → 64.7% of seats (+9.3 pts gap) |
| 2019 | Colchester | 17 | 1 | 5.9% | Liberal Democrats · 26.6% of votes → 35.3% of seats (+8.7 pts gap) |
| 2019 | Derby | 17 | 1 | 5.9% | Independent · 4.3% of votes → 5.9% of seats (+1.6 pts gap) |
| 2019 | Solihull | 17 | 1 | 5.9% | Independent · 3.1% of votes → 5.9% of seats (+2.8 pts gap) |
| 2019 | Thurrock | 17 | 1 | 5.9% | Independent · 4.0% of votes → 5.9% of seats (+1.9 pts gap) |
| 2018 | Southend-on-Sea | 17 | 1 | 5.9% | Conservative Party · 36.8% of votes → 47.1% of seats (+10.3 pts gap) |
| 2016 | Solihull | 17 | 1 | 5.9% | Liberal Democrats · 11.2% of votes → 17.6% of seats (+6.4 pts gap) |
| 2016 | South Lakeland | 17 | 1 | 5.9% | Conservative Party · 36.3% of votes → 41.2% of seats (+4.9 pts gap) |
| 2024 | Colchester | 18 | 1 | 5.6% | Conservative Party · 30.0% of votes → 38.9% of seats (+8.9 pts gap) |
| 2022 | Colchester | 18 | 1 | 5.6% | Labour Party · 28.2% of votes → 33.3% of seats (+5.2 pts gap) |
| 2022 | Maidstone | 18 | 1 | 5.6% | Liberal Democrats · 24.5% of votes → 33.3% of seats (+8.8 pts gap) |
| 2021 | Ipswich | 18 | 1 | 5.6% | Labour Party · 39.2% of votes → 44.4% of seats (+5.2 pts gap) |
| 2019 | Welwyn Hatfield | 18 | 1 | 5.6% | Conservative Party · 38.6% of votes → 44.4% of seats (+5.9 pts gap) |
| 2018 | Maidstone | 18 | 1 | 5.6% | Independent · 4.6% of votes → 5.6% of seats (+0.9 pts gap) |
| 2016 | Pendle | 18 | 1 | 5.6% | Conservative Party · 41.4% of votes → 50.0% of seats (+8.6 pts gap) |
| 2016 | Preston | 18 | 1 | 5.6% | Labour Party · 45.8% of votes → 55.6% of seats (+9.8 pts gap) |
| 2016 | West Lancashire | 18 | 1 | 5.6% | Labour Party · 56.1% of votes → 66.7% of seats (+10.5 pts gap) |
| 2024 | Kingston Upon Hull, City of | 19 | 1 | 5.3% | Labour Party · 44.1% of votes → 52.6% of seats (+8.5 pts gap) |
| 2022 | Basingstoke and Deane | 19 | 1 | 5.3% | B&D IND · 14.6% of votes → 21.1% of seats (+6.4 pts gap) |
| 2021 | Colchester | 19 | 1 | 5.3% | Independent · 1.7% of votes → 5.3% of seats (+3.5 pts gap) |
| 2021 | Bury | 19 | 1 | 5.3% | RADF · 5.5% of votes → 10.5% of seats (+5.0 pts gap) |
| 2021 | Calderdale | 19 | 1 | 5.3% | Conservative Party · 39.0% of votes → 47.4% of seats (+8.3 pts gap) |
| 2018 | Swindon | 19 | 1 | 5.3% | Conservative Party · 41.4% of votes → 47.4% of seats (+5.9 pts gap) |
| 2018 | Welwyn Hatfield | 19 | 1 | 5.3% | Liberal Democrats · 24.7% of votes → 31.6% of seats (+6.9 pts gap) |
| 2024 | Oldham | 20 | 1 | 5.0% | Labour Party · 29.1% of votes → 35.0% of seats (+5.9 pts gap) |
| 2023 | Kingston Upon Hull | 20 | 1 | 5.0% | Liberal Democrats · 48.6% of votes → 55.0% of seats (+6.4 pts gap) |
| 2022 | West Lancashire | 20 | 1 | 5.0% | Conservative Party · 35.2% of votes → 40.0% of seats (+4.8 pts gap) |
| 2022 | Oldham | 21 | 1 | 4.8% | FIP · 5.1% of votes → 9.5% of seats (+4.4 pts gap) |
| 2016 | Trafford | 21 | 1 | 4.8% | Conservative Party · 39.8% of votes → 47.6% of seats (+7.8 pts gap) |
| 2018 | Wirral | 23 | 1 | 4.3% | Labour Party · 44.8% of votes → 52.2% of seats (+7.4 pts gap) |
| 2022 | Dudley | 25 | 1 | 4.0% | Labour Party · 42.4% of votes → 48.0% of seats (+5.6 pts gap) |
| 2019 | Maldon | 29 | 1 | 3.4% | Conservative Party · 46.1% of votes → 51.7% of seats (+5.6 pts gap) |
| 2019 | South Holland | 32 | 1 | 3.1% | Conservative Party · 54.4% of votes → 59.4% of seats (+4.9 pts gap) |
| 2023 | North Warwickshire | 35 | 1 | 2.9% | Independent · 5.6% of votes → 8.6% of seats (+3.0 pts gap) |
| 2019 | North Warwickshire | 35 | 1 | 2.9% | Conservative Party · 54.5% of votes → 60.0% of seats (+5.5 pts gap) |
| 2019 | Crawley | 36 | 1 | 2.8% | Labour Party · 47.0% of votes → 52.8% of seats (+5.8 pts gap) |
| 2023 | Hertsmere | 39 | 1 | 2.6% | Labour Party · 32.9% of votes → 35.9% of seats (+3.0 pts gap) |
| 2023 | Great Yarmouth | 39 | 1 | 2.6% | Conservative Party · 43.6% of votes → 48.7% of seats (+5.2 pts gap) |
| 2019 | Great Yarmouth | 39 | 1 | 2.6% | Labour Party · 36.6% of votes → 38.5% of seats (+1.9 pts gap) |
| 2023 | Stafford | 40 | 1 | 2.5% | Labour Party · 29.1% of votes → 32.5% of seats (+3.4 pts gap) |
| 2023 | Tonbridge & Malling | 44 | 1 | 2.3% | Conservative Party · 40.2% of votes → 45.5% of seats (+5.3 pts gap) |
| 2019 | Stoke-on-Trent | 44 | 1 | 2.3% | Labour Party · 32.4% of votes → 36.4% of seats (+3.9 pts gap) |
| 2023 | Bedford | 46 | 1 | 2.2% | Conservative Party · 27.8% of votes → 30.4% of seats (+2.6 pts gap) |
| 2017 | Flintshire | 56 | 1 | 1.8% | Liberal Democrats · 8.0% of votes → 8.9% of seats (+0.9 pts gap) |
| 2022 | Hyndburn | 12 | 0 | 0.0% | — |
| 2022 | Rugby | 14 | 0 | 0.0% | — |
| 2021 | Stevenage | 14 | 0 | 0.0% | — |
| 2021 | West Lancashire | 19 | 0 | 0.0% | — |
| 2021 | Lincoln | 11 | 0 | 0.0% | — |
| 2021 | Wirral | 23 | 0 | 0.0% | — |
| 2021 | Worcester | 12 | 0 | 0.0% | — |
| 2019 | Brentwood | 12 | 0 | 0.0% | — |
| 2019 | Cambridgeshire | 1 | 0 | 0.0% | — |
| 2019 | Durham | 2 | 0 | 0.0% | — |
| 2019 | Gloucestershire | 1 | 0 | 0.0% | — |
| 2019 | Northumberland | 1 | 0 | 0.0% | — |
| 2019 | Surrey | 1 | 0 | 0.0% | — |
| 2019 | West Sussex | 1 | 0 | 0.0% | — |
| 2019 | Woking | 10 | 0 | 0.0% | — |
| 2018 | Carlisle | 17 | 0 | 0.0% | — |
| 2018 | Cheshire West and Chester | 1 | 0 | 0.0% | — |
| 2018 | Great Yarmouth | 14 | 0 | 0.0% | — |
| 2018 | Warwickshire | 1 | 0 | 0.0% | — |
| 2018 | West Lancashire | 18 | 0 | 0.0% | — |
| 2018 | Weymouth and Portland | 1 | 0 | 0.0% | — |
| 2017 | Birmingham | 2 | 0 | 0.0% | — |
| 2017 | Blackburn with Darwen | 1 | 0 | 0.0% | — |
| 2017 | Bradford | 1 | 0 | 0.0% | — |
| 2017 | Breckland | 1 | 0 | 0.0% | — |
| 2017 | Bury | 1 | 0 | 0.0% | — |
| 2017 | Cambridge | 1 | 0 | 0.0% | — |
| 2017 | Camden | 1 | 0 | 0.0% | — |
| 2017 | Carlisle | 2 | 0 | 0.0% | — |
| 2017 | Central Bedfordshire | 2 | 0 | 0.0% | — |
| 2017 | Chelmsford | 1 | 0 | 0.0% | — |
| 2017 | Cheltenham | 1 | 0 | 0.0% | — |
| 2017 | Craven | 1 | 0 | 0.0% | — |
| 2017 | Crawley | 1 | 0 | 0.0% | — |
| 2017 | Dacorum | 1 | 0 | 0.0% | — |
| 2017 | Daventry | 1 | 0 | 0.0% | — |
| 2017 | Eastleigh | 1 | 0 | 0.0% | — |
| 2017 | Exeter | 1 | 0 | 0.0% | — |
| 2017 | Hartlepool | 1 | 0 | 0.0% | — |
| 2017 | Havant | 1 | 0 | 0.0% | — |
| 2017 | Huntingdonshire | 1 | 0 | 0.0% | — |
| 2017 | Ipswich | 1 | 0 | 0.0% | — |
| 2017 | Isles of Scilly | 12 | 0 | 0.0% | — |
| 2017 | Liverpool | 1 | 0 | 0.0% | — |
| 2017 | Maidstone | 1 | 0 | 0.0% | — |
| 2017 | Malvern Hills | 1 | 0 | 0.0% | — |
| 2017 | Manchester | 1 | 0 | 0.0% | — |
| 2017 | Mendip | 1 | 0 | 0.0% | — |
| 2017 | Mid Suffolk | 1 | 0 | 0.0% | — |
| 2017 | Newark and Sherwood | 1 | 0 | 0.0% | — |
| 2017 | North Dorset | 1 | 0 | 0.0% | — |
| 2017 | Nottingham | 1 | 0 | 0.0% | — |
| 2017 | Nuneaton and Bedworth | 1 | 0 | 0.0% | — |
| 2017 | Oxford | 1 | 0 | 0.0% | — |
| 2017 | Preston | 2 | 0 | 0.0% | — |
| 2017 | Reigate and Banstead | 1 | 0 | 0.0% | — |
| 2017 | Rugby | 2 | 0 | 0.0% | — |
| 2017 | Runnymede | 1 | 0 | 0.0% | — |
| 2017 | Rushcliffe | 1 | 0 | 0.0% | — |
| 2017 | Rushmoor | 1 | 0 | 0.0% | — |
| 2017 | Sedgemoor | 1 | 0 | 0.0% | — |
| 2017 | Sheffield | 1 | 0 | 0.0% | — |
| 2017 | Slough | 1 | 0 | 0.0% | — |
| 2017 | South Cambridgeshire | 1 | 0 | 0.0% | — |
| 2017 | South Lakeland | 1 | 0 | 0.0% | — |
| 2017 | Spelthorne | 1 | 0 | 0.0% | — |
| 2017 | Stevenage | 1 | 0 | 0.0% | — |
| 2017 | Test Valley | 1 | 0 | 0.0% | — |
| 2017 | Trafford | 1 | 0 | 0.0% | — |
| 2017 | Welwyn Hatfield | 1 | 0 | 0.0% | — |
| 2017 | West Devon | 1 | 0 | 0.0% | — |
| 2017 | West Oxfordshire | 1 | 0 | 0.0% | — |
| 2017 | Weymouth and Portland | 1 | 0 | 0.0% | — |
| 2017 | Windsor and Maidenhead | 1 | 0 | 0.0% | — |
| 2017 | Wirral | 1 | 0 | 0.0% | — |
| 2017 | Wyre Forest | 1 | 0 | 0.0% | — |
| 2016 | Barnet | 1 | 0 | 0.0% | — |
| 2016 | Barrow-in-Furness | 1 | 0 | 0.0% | — |
| 2016 | Breckland | 1 | 0 | 0.0% | — |
| 2016 | Brent | 1 | 0 | 0.0% | — |
| 2016 | Canterbury | 1 | 0 | 0.0% | — |
| 2016 | Croydon | 1 | 0 | 0.0% | — |
| 2016 | Doncaster | 1 | 0 | 0.0% | — |
| 2016 | East Riding | 1 | 0 | 0.0% | — |
| 2016 | Gloucestershire | 1 | 0 | 0.0% | — |
| 2016 | Great Yarmouth | 13 | 0 | 0.0% | — |
| 2016 | Greenwich | 1 | 0 | 0.0% | — |
| 2016 | Guildford | 1 | 0 | 0.0% | — |
| 2016 | Hackney | 2 | 0 | 0.0% | — |
| 2016 | Havering | 1 | 0 | 0.0% | — |
| 2016 | Kensington and Chelsea | 2 | 0 | 0.0% | — |
| 2016 | Merton | 1 | 0 | 0.0% | — |
| 2016 | North Dorset | 2 | 0 | 0.0% | — |
| 2016 | Redbridge | 1 | 0 | 0.0% | — |
| 2016 | St Edmundsbury | 1 | 0 | 0.0% | — |
| 2016 | South Ribble | 1 | 0 | 0.0% | — |
| 2016 | Southwark | 2 | 0 | 0.0% | — |
| 2016 | Spelthorne | 1 | 0 | 0.0% | — |
| 2016 | Swansea | 1 | 0 | 0.0% | — |
| 2016 | Tendring | 1 | 0 | 0.0% | — |
| 2016 | Waveney | 1 | 0 | 0.0% | — |
| 2016 | Westminster | 1 | 0 | 0.0% | — |