Polling stations have closed in by-elections that could deliver a triple blow to Rishi Sunak – with the Liberal Democrats already claiming victory in one seat.

The results from Uxbridge and South Ruislip in west London, Selby and Ainsty in North Yorkshire, and Somerton and Frome in Somerset, are expected in the early hours of Friday morning.

The three seats were left empty by outgoing Conservative MPs – former prime minister Boris Johnson, Nigel Adams, and David Warburton, who has been an independent since last year.

Follow by-election coverage live: Tories expect to lose all three by-elections, Sky News told

According to political editor Beth Rigby, Mr Sunak‘s party are bracing to lose all three constituencies.

Mr Johnson had a majority of 7,210 when Uxbridge and South Ruislip was last contested at the general election in 2019, with Labour coming in second place.

Selby and Ainsty saw Mr Adams elected in the same year with a majority of over 20,000, again with Labour as the runner-up.

And Mr Warburton’s seat of Somerton and Frome saw him get a 19,213 majority in 2019, though it was the Liberal Democrats who came the closest to him.

A Conservative spokesperson said they knew the votes were always going to be “very challenging”, especially “given the circumstances in which they were brought about”.

It is common for sitting governments to perform poorly in by-elections, but it is also common for parties to talk down their chances, so they can frame a positive result as an unexpected success.

The Liberal Democrats claimed victory in Somerton and Frome before midnight – although of third of ballots were still waiting to be counted – overturning a majority of close to 20,000.

Christine Jardine, MP for Edinburgh West, told Sky News: “We’ve won this quite decisively, the Conservative vote is just collapsing, and I think that’s indicative of how people here feel about how the government has let them down over the past five years.”

She added that the Lib Dems are experiencing a “new period of growth” and they have “romped home”.

A Labour spokesman said they “don’t know if we’ve made it over the line” in the other two seats – but claimed that “Keir Starmer’s leadership of a changed Labour Party, back in the service of working people, has seen voters put their trust in us”.

While the cost of living was the main factor in Uxbridge and South Ruislip, local factors – specifically the ULEZ expansion – understood to have dampened Labour support in the seat, with party insiders believing the vote could still go either way.

Labour MP Steve Reed told Sky News at the Uxbridge and South Ruislip count that he was “not going to predict” which was the vote would go – and claimed the election was “always going to be close”.

Former Conservative minister Sir Robert Buckland told Sky News he reckoned his party will lose all three votes.

He said: “Being realistic and frank, if, as I expect, we don’t do well tonight we need to reflect on that.

“I think it’s going to be a difficult night for us.”

Ballot boxes began to be opened and votes counted from 10pm.

Results are not expected until the small hours of the morning at the earliest – especially if the results are close.