Can Boris Johnson hold on to power? ITV News Deputy Political Editor Anushka Asthana reports
A senior Conservative MP has accused Number 10 of "blackmail", saying staff had threatened him and other colleagues over their opposition to Boris Johnson.
William Wragg urged MPs to contact the Metropolitan Police if they had been threatened or intimidated.
The chair of the Public Administration and Constitutional Affairs Committee said Number 10 staff, special advisers and government ministers had said there would be embarrassing stories released to the press if MPs did not support the prime minister.
He also said Number 10 had threatened to withdraw funding to his and other backbenchers' constituencies if they did not withdraw their opposition to Mr Johnson.
He said "the intimidation of a member of parliament is a serious matter", adding: "The reports of which I'm aware would seem to constitute blackmail."
"As such it would be my general advice to colleagues to report these matters to the Speaker of the House of Commons and the Commissioner of Metropolitan Police."
The PM said there is "no evidence to support any of those allegations".
Number 10 said "If there is any evidence to support these claims we would look at it very carefully".
Asked if he would look for evidence, Mr Johnson said: "Of course."
Former Tory MP Christian Wakeford, who defected to Labour on Wednesday, claimed he was threatened about the loss of a school in his constituency if he did not vote along party lines.
The Bury South MP said the "threats" made him start to question his place within the Conservative Party, which he had been a member of for two decades.
"I was threatened that I would not get the school for Radcliffe if I did not vote in one particular way.
"This is a town that's not had a high school for the best part of 10 years, and how would you feel when holding back the regeneration of a town for a vote?
"It didn't sit comfortably and that was when I was really starting to question my place, where I was, and ultimately where I am now."
A spokeswoman for the Speaker's Office said: "If the matters are criminal, they should be referred to the police. If it is a matter of privilege, the Speaker should be informed in the first instance."
Deputy Labour leader Angela Rayner called for the "shocking accusations" of bullying and blackmail to be investigated.
She tweeted: "These are shocking accusations of bullying, blackmail (and) bad behaviour from people in positions of power.
"We need this to be investigated thoroughly."
SNP leader Nicola Sturgeon said the accusations not only amount to blackmail and intimidation "but it is also corruption".
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Downing Street said there are no plans to launch an inquiry into Mr Wragg's accusations.
But Scottish Conservatives leader Douglas Ross - who is one of several senior Tories calling on the PM to quit - said the "serious" allegations should be investigated, although he said he had not been the subject of such behaviour himself.
One of the PM's most passionate supporters, Nadine Dorries, said Mr Wragg was "attention seeking" with his accusation as she insisted intimidation tactics are not used by government whips.
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The MP is one of seven Conservatives to publicly call on the PM to resign over the partygate scandal - there had been eight before Mr Wakeford defected to Labour on Wednesday.
He was one of the first to make the demand publicly, however it is understood that more than 20 have anonymously submitted letters of no confidence in the PM.
Mr Wragg - who has also submitted a no confidence letter - said he was "particularly concerned as a Conservative MP" by the behaviour of the PM.
"The prime minister's position is untenable and I don't believe it should be left to the findings of a civil servant to determine the future of the prime minister, and indeed, who governs this country," he told the BBC.
His intervention came after Mr Johnson admitted breaking lockdown rules by attending a party in his Number 10 garden, but he attempted to explain wrongdoing by claiming he thought it was a work event.
That claim was called into question by an email, sent by the PM's principal private secretary Martin Reynolds and leaked to ITV News, which invited more than 100 Number 10 staff to "make the most of lovely weather" by attending "socially distanced drinks".
Mr Johnson has repeatedly claimed he didn't know the party was in breach of the rules and insists no one told him it was.