By-election news - live: PM loses backing of more Tory MPs after disastrous defeats

Ed Davey has been speaking in Tiverton and Honiton where the party won last night's byelection - and he has a new prop.

The Lib Dem leader appeared alongside a blue door with "it's time to show Boris the door" written across it.

When the Lib Dems won the Cheshire and Amersham byelection last year, he posed with a hammer in front of a wall of blue bricks, claiming his party was ready to smash the Tories 'blue wall' of seats across southern England.

We'll have the main takeaways from Davey's speech shortly.

Labour and the Liberal Democrats were urged to forge an electoral pact to remove the Conservatives at the next general election after “industrial-scale” tactical voting saw Boris Johnson’s party lose two by-elections.

Our politics correspondent Adam Forrest reports:

Close attention has been paid to Rishi Sunak - a close ally of Oliver Dowden - this morning to see if he might also resign following the byelection defeats.

The chancellor has within the past half an hour vowed to carry on, although there was no mention of Boris Johnson in his statement.

"I’m sad that my colleague and friend @OliverDowden took the decision to resign this morning.

"We all take responsibility for the results and I’m determined to continue working to tackle the cost of living, including delivering NICs changes saving 30 million people on average £330."

Speaking from the Royal Highland Show on Friday, Scottish first minister Ms Sturgeon urged Tory MPs to remove Boris Johnson.

"It's a monumental, massive, humiliating vote of no confidence in Boris Johnson," she said.

"People could see it coming 100 miles off and it should send a very strong message - if not to Boris Johnson, who is impervious to all of these things given his arrogance, it should send a very strong message to the Conservatives.

"If they keep Boris Johnson, a law breaking prime minister who has been seen to not tell the truth, if they keep him in office, then effectively they are all becoming complicit in this.

"If this is not a wake-up call to the Conservative Party, then it will just prove beyond doubt that they don't have the interests of any part of the UK in mind or at heart."

The Tories can't win a majority at the next general election under Boris Johnson, a polling expert has said in the wake of last night's byelection defeats.

Peter Kellner, former president of YouGov, spoke to Sky News earlier.

Mr Kellner also claimed the two by-elections were a referendum on the prime minister's leadership.

"I've been saying for some time that I don't think the Conservatives can win under Boris Johnson," he said.

"I was saying that based on polls. But when you do get real votes in two very different parts of the country...the Conservative gets hammered in both...I would have thought the Tories' only chance is to change leader."

Tory grandee Sir Geoffrey Clifton-Brown said there is "no doubt" it would be "difficult to hold" his seat if there were a by-election in his constituency now.

Speaking to BBC Radio 4's Today programme, the MP for the Cotswolds and treasurer of the 1922 committee said: "I think, factually, if I were to run under a bus today it would be difficult to hold my seat. There's no doubt about that.

"I feel very sorry for all our volunteers, and indeed my colleagues, and indeed myself, who work very hard in these by-elections, but were simply defeated by the situation that we find ourselves in at the moment."

Cabinet minister Oliver Dowden quit because he "can't go on defending the indefensible", a senior Tory has suggested.

Mr Dowden resigned shortly after the Tories lost by-elections in Wakefield and Tiverton & Honiton, where Partygate was again raised as an issue by voters.

"That Oliver Dowden has resigned is...significant," Sir Roger Gale, the North Thanet MP said.

"Oliver is an honourable and decent man and he's obviously decided that he can't go on defending the indefensible".

Oliver Dowden took a “personal view” on Boris Johnson in his resignation letter this morning, a government minister has said.

Paul Scully, the business minister, defended the PM’s “brazen approach” and insisted he would come up with “big ideas” to get the UK’s flailing economy back on track.

Mr Scully also said that the party did not need the “psychodrama” of leadership campaigns while inflation was spiralling.

Boris Johnson is a "useless, lying crook", Alastair Campbell has said after the prime minister led his party to two defeats in last night's by-elections.

The former Labour spin doctor spoke to Sky News earlier after the Tories lost Wakefield to Labour and Tiverton and Honiton to the Lib Dems.

"The guy can't do the job," Mr Campbell said. "They all [Tory MPs] know he can't do the job.

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Tory MP Robert Buckland blamed the cost of living and “deep concern” over Partygate for “very bad results” last night, Adam Forrest, our politics correspondent, reports.

The former minister said Mr Dowden’s resignation would create “further problems” for Mr Johnson – and called for the party to return to “mainstream, moderate opinion”.

But he defended his decision to support the PM at the recent confidence vote, saying it would be wrong to think that “removing another prime minister is job done”, adding: “I don’t think throwing over the captain now would be the right response.”