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Insights

By-election upsets

By-elections since 2010 where the seat changed hands, with the swing.

DateConstituencyGained byFromSwingMajority
26 Feb 2026Gorton and DentonGrn Hannah SpencerLab26.4 pts4,402
1 May 2025Runcorn and HelsbyRef Sarah Joanne PochinLab17.4 pts6
2 May 2024Blackpool SouthLab Chris WebbCon26.3 pts7,607
29 Feb 2024RochdaleWPB George GallowayLab41.8 pts5,697
15 Feb 2024KingswoodLab Damien EganCon16.4 pts2,501
15 Feb 2024WellingboroughLab Gen KitchenCon28.5 pts6,436
19 Oct 2023Mid BedfordshireLab Alistair StrathernCon20.5 pts1,192
19 Oct 2023TamworthLab Sarah EdwardsCon23.9 pts1,316
5 Oct 2023Rutherglen and Hamilton WestLab Michael ShanksSNP20.4 pts9,446
20 Jul 2023Selby and AinstyLab Keir MatherCon23.7 pts4,161
20 Jul 2023Somerton and FromeLD Sarah DykeCon29.0 pts11,008
23 Jun 2022Tiverton and HonitonLD Richard FoordCon29.9 pts6,144
23 Jun 2022WakefieldLab Simon LightwoodCon12.7 pts4,925
16 Dec 2021North ShropshireLD Helen MorganCon34.2 pts5,925
17 Jun 2021Chesham and AmershamLD Sarah GreenCon25.1 pts8,028
6 May 2021HartlepoolCon Jill MortimerLab16.0 pts6,940
1 Aug 2019Brecon and RadnorshireLD Jane DoddsCon12.0 pts1,425
23 Feb 2017CopelandCon Trudy HarrisonLab6.7 pts2,147
1 Dec 2016Richmond ParkLD Sarah OlneyCon44.3 pts1,872
20 Nov 2014Rochester and StroodUKIP Mark RecklessCon28.2 pts2,920
9 Oct 2014ClactonUKIP Douglas CarswellCon44.1 pts12,404
15 Nov 2012CorbyLab Andrew SawfordCon12.7 pts7,791
29 Mar 2012Bradford WestRes George GallowayLab36.6 pts10,140

Swing is Butler swing from the losing party to the winner since the previous election in the seat.

Official results House of Commons Library and UK Parliament election results data. Contains Parliamentary information licensed under the Open Parliament Licence v3.0. How we use this data