On 20 July 2023, a trio of parliamentary by-elections saw the available seats apportioned among the three main parties – with all of the Labour, Conservative and Liberal Democrat parties securing wins.

The contests, held simultaneously in Selby and Ainsty, Somerton and Frome, and Uxbridge and South Ruislip, were triggered by the resignations of Conservative MPs Boris Johnson, Nigel Adams and David Warburton.

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All of Adams, Warburton and Johnson had stood down in controversial circumstances.

At the time of his resignation, Warburton had been facing accusations of sexual harassment and drug abuse – allegations which befit a narrative of Conservative “sleaze”.

Johnson, meanwhile, resigned in protest at the commons privileges committee’s report into “Partygate”. The former prime minister had been given advanced sight of the report, which found he misled the House. Johnson stepped down as an MP rather than face a likely recall petition.

Adams, a strong supporter of the ex-prime minister, resigned alongside Johnson in solidarity and protest.

In Selby and Ainsty (North Yorkshire), the Labour Party achieved a historic victory. Keir Mather overturned a Conservative majority of 20,137 from the 2019 general election, winning with a majority of 4,161 on a remarkable swing of 23.7% – one of the largest such swings to Labour from the Conservatives since the Second World War.

In Somerton and Frome (Somerset) the Liberal Democrats secured an even more dramatic win. Sarah Dyke overturned a Conservative majority of 19,213, winning by 11,008 votes on a swing of 29%. The result validated the Liberal Democrats’ electoral strategy of targeting Conservative strongholds in the so-called “blue wall”.

The only consolation for the government came in Uxbridge and South Ruislip (London), which had been vacated by Johnson. The Conservative candidate, Steve Tuckwell, held the seat by a margin of just 495 votes. The significantly smaller swing against the Conservatives here (6.7%) was widely attributed to local opposition to the planned expansion of London’s Ultra Low Emission Zone (Ulez) by the London mayor, Sadiq Khan. This prompted Keir Starmer, the Labour leader of the opposition, to distance himself from the scheme. Starmer said Ulez was “the reason we didn’t win” in Uxbridge, saying “we’ve all got to reflect on that, including the mayor”.

The Selby and Somerton contests spoke to a remarkably developed “get the Tories out” fervour.

The Uxbridge result offered some relief for the embattled prime minister, Rishi Sunak; however, the outcome reflected the contest’s distinctive character – rather than any meaningful revival in the Conservative Party’s fortunes.

Nevertheless, Sunak seized on the result, journeying to Uxbridge to bask in his party’s by-election victory. The contest may also have marked a turning point for the government’s green and environmental policy. Sunak subsequently doubled down on his opposition to Ulez-style schemes and scaled back the government’s net zero commitments.

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But this initiative failed to revive his party’s position.

The 2024 general election resulted in a spectacular landslide victory for Starmer’s Labour Party, bringing 14 years of Conservative government to a definitive end. Labour secured 411 seats and a commanding House of Commons majority of 174.

The election represented the worst defeat in the history of the Conservative Party, which was reduced to just 121 MPs.

Steve Tuckwell lost his Uxbridge and South Ruislip seat, having served less than a year in parliament.