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Explainer

By-elections since the 2024 general election

Labour has lost two by-elections since the 2024 general election.

Hannah Spencer from the Green Party addresses the press and supporters after winning the by-election in Gorton and Denton.
Hannah Spencer from the Green Party addresses the press and supporters after winning the by-election in Gorton and Denton in February 2026.

On 18 June 2026, three by-elections – an election for MPs that takes place between general elections – will take place. One in Makerfield, where the former Labour MP Josh Simons stood down to allow Andy Burnham, the Mayor of Greater Manchester, to stand for election in the constituency. And two in Scotland – in Aberdeen South and Arbroath and Broughty Ferry – to replace two former SNP MPs after they were elected to represent seats in the Scottish Parliament in May’s devolved elections.

Which parties have won the recent by-elections?

Labour has lost two by-elections since the 2024 general election. The Green Party won the Gorton and Denton by-election in February 2026, and Reform UK won the Runcorn and Helsby by-election in May 2025. 

Hannah Spencer from the Green Party won the Gorton and Denton seat with a majority of 4,402 votes, securing 41% of all the votes cast. Labour previously won the seat at the 2024 general election with 51% of the total vote and a majority of 13,413 votes.

In the Runcorn and Helsby by-election in May 2025, Sarah Pochin from Reform UK won the seat from the Labour Party with just a six-vote majority. 

Why was there a by-election in Gorton and Denton?

The by-election was triggered after the former Labour MP Andrew Gwynne resigned on medical grounds on 22 January 2026. Gwynne was an Independent MP at the time, having been suspended from the Labour Party in February 2025 following the revelation of inappropriate WhatsApp messages he had sent.

Why was there a by-election in Runcorn and Helsby in May 2025?

Mike Amesbury, who was initially elected in 2024 as a Labour MP, stepped down on 17 March 2025, triggering a by-election in Runcorn and Helsby which was held on 1 May 2025.

Amesbury resigned after pleading guilty to assault and was sentenced to 10 weeks in prison (the sentence was later suspended). Following the initial incident, Amesbury was suspended from the Labour Party and sat in the Commons as an independent MP. Amesbury has stated that he would have remained in place if he had not been given prison time. But by being sentenced to prison, one of the criteria for a recall petition had already been met, meaning that a by-election would have been triggered if more than 10% of constituency votes signed the petition.

How long does it take for a by-election to take place after an MP leaves office?

When an MP’s seat becomes vacant, the chief whip of the relevant political party (or another MP in the case of independents) moves a motion requesting that a new writ is issued for an election – this is known as ‘moving the Writ’. The Writ will typically be issued within three months of the seat becoming vacant and a by-election will take place between 21 and 27 days from this point. 7 UK Parliament, ‘By-elections’, www.parliament.uk/about/how/elections-and-voting/by-elections/

Do MPs continue to receive a salary in the lead-up to a by-election?

MPs continue to receive their salary until they step down. MPs are not employed in the normal way – they are paid by the Independent Parliamentary Standards Authority (IPSA), which has no discretion to withhold MPs pay except for any period where an MP has been suspended from the House. Equally, MPs have no choice but to be paid so long as they serve as an MP. 8 IPSA, ‘MPs’ pay facts’, 5 December 2022, www.theipsa.org.uk/news/mps-pay-facts

How do by-elections affect the amount of public money that parties receive?

By-elections do not impact the level of public funding that parties receive. The major source of public funding for political parties in opposition is Short Money. This is allocated to parties based only on a combination of the number of seats won and the number of votes received at the last general election – by-election results do not alter this calculation.

By-elections

A parliamentary by-election in the UK takes place when a seat in the House of Commons becomes vacant between general elections. But how are they triggered?

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