UK by-elections: Which seats are being fought and why?

Conservatives bracing for tough battle in three constituencies triggered by high-profile resignations

People walk outside a polling station during a by-election for Britain's parliamentary constituency of Uxbridge and South Ruislip in west London. EPA

Thousands of people have taken to the ballot box in three constituencies across England on Thursday with the ruling Conservative Party bracing for a 'tough battle' to retain its seats.

The results, which will begin to emerge on Friday, will say much about the public's feeling towards the current government, led by Prime Minister Rishi Sunak.

All three contests were triggered following high-profile resignations. Here's what to expect in the triple by-election:

Uxbridge and South Ruislip

Boris Johnson triggered a by-election when he resigned from the West London constituency in protest after a parliamentary watchdog found that he had misled the House of Commons over his lockdown-breaking parties while prime minister. Mr Johnson had been the area's MP since 2015.

The constituency, situated on the western borders of London, has a larger retired population than many other inner-city areas of the capital, and voted in favour of staying in the EU during the 2016 Brexit referendum.

A major election issue in the car-dependent suburb is the expansion of the Ultra-low Emissions Zone (Ulez), favoured by current London mayor Sadiq Khan.

Roughly 70,000 people are eligible to vote in the by-election. The Conservatives won the seat by a 7,000 majority in the 2019 general election, garnering 25,000 votes in total.

Standing in the election is Labour's Danny Beale and Mr Johnson's Tory party replacement Steve Tuckwell. Other candidates include Piers Corbyn, the brother of former Labour leader Jeremy; actor and social media personality Laurence Fox; and Howling Laud Hope from the Monster Raving Loony party.

By-election winner and Labour Party MP Keir Mather arrives at the Selby Leisure Centre in North Yorkshire. PA

Conservative MP Steve Tuckwell poses for selfies after winning the Uxbridge and South Ruislip by-election. PA

Sarah Dyke, a Liberal Democrat, won the Somerton and Frome by-election. PA

Candidates Leo Phaure, Kingsley Hamilton, Steve Gardner and Piers Corbyn stage an anti-Ulez protest on stage after Mr Tuckwell won the Uxbridge and South Ruislip by-election. PA

Mr Mather speaks at Selby Leisure Centre. PA

Mr Tuckwell shakes hands with Labour candidate Danny Beales in South Ruislip. PA

Ballots are counted in South Ruislip. PA

Laurence Fox of the Reclaim Party poses for a photograph in South Ruislip. PA

Votes are counted in Selby. PA

Ballot boxes arrive in Selby. PA

A man adjusts a polling station sign in Womersley, part of the Selby and Ainsty constituency, in North Yorkshire. PA

Mr Beales, left, Labour candidate for Uxbridge and South Ruislip, after casting his vote in the constituency. PA

Voters go to the polls in Selby. Getty

Simon Lightwood, Labour MP for Wakefield, pets a dog as he campaigns on polling day in Selby. Getty

A voter arrives a polling station at Selby Community Centre in North Yorkshire. PA

A dog waits outside a polling station in Selby. Getty

Mr Tuckwell leaves after casting his vote in Uxbridge. Getty

Selby and Ainsty

This by-election was triggered after the resignation of Nigel Adams, a staunch ally of Mr Johnson, when he was passed over for a peerage in the PM's outgoing resignation honours list.

Mr Adams' decision to step down created a vacancy in this largely rural North Yorkshire constituency, which was created at the 2010 general election and has always been held by the Conservatives. More than 78,000 people are eligible to vote in the seat.

Parties hoping to emerge triumphant will need to overturn a 20,000 vote majority, which was gathered by the Tories in the 2019 general election.

The Tories have named barrister and district councillor Claire Holmes as their candidate and Labour have selected 25-year-old Keir Mather to fight for the seat.

If he was elected, Mr Mather would be the youngest MP in the Commons, as the current youngest, Labour’s Nottingham East MP Nadia Whittome, is 26.

The Lib Dems, who came third in the seat in the 2019 general election, have selected North Yorkshire councillor and NHS manager Matt Walker.

Somerset & Frome

The contest in this seat was triggered by David Warburton quitting after admitting cocaine use amid allegations of sexual harassment. He had held the seat since 2015 when the Tories took it from the Lib Dems.

Somerton & Frome has a long history of being a two-horse race between the Conservatives and the Liberal Democrats. The seat has an electorate of 85,000 and the turnout was 75 per cent in the last election, above the national average.

The Tories held it from 1983 to 1997 and the Lib Dems from 1997 until 2015, when David Warburton won it back for the Conservatives.

Mr Warburton had a majority of 19,213 at the 2019 election and took nearly 56 per cent of the vote, with the Lib Dems second on just over 26 per cent and Labour third on 13 per cent.

Mr Warburton sat as an independent MP between April 2022 and his resignation in June 2023, after losing the Conservative whip due to allegations of misconduct.

Faye Purbrick, who sits on Yeovil Town Council and Somerset County Council, is the Conservative candidate to replace Mr Warburton.

The Lib Dem's candidate is Sarah Dyke, a Somerset Council councillor and former member of South Somerset District Council. She lives in the constituency and is from a Somerset farming family.

Other candidates standing in the Somerton and Frome by-election include the Green Party's Martin Dimery, Neil Guild of Labour, and Peter Richardson of the UK Independence Party.