Top Tory MP Tobias Ellwood today announced he will be submitting a letter of no confidence in Boris Johnson.
The former minister and current Defence Committee chairman is one of the most senior Tories yet to demand the Prime Minister quit.
It ramps up the danger of 54 MPs submitting letters to trigger a no confidence vote, after David Davis and Andrew Mitchell also publicly said the PM should go. Mr Davis later confirmed he had not actually submitted a letter.
The MP made the bombshell announcement just as Boris Johnson jetted back from Ukraine to face the music from his own party at PMQs.
The PM is facing anger from his own party after the Sue Gray report blasted "failures of leadership" over No10 parties, and he then refused to withdraw a false "slur" that Keir Starmer failed to prosecute Jimmy Savile in his previous job.
Speaking on Sky News, Mr Ellwood said: “This is just horrible for all MPs to continuously have to defend this to the British public.
“The Government’s acknowledged the need for fundamental change, culture, make-up, discipline, the tone of Number 10, but the strategy has been one, it seems, of survival, of rushed policy announcements like the Navy taking over the migrant Channel crossings.
“And attacking this week Keir Starmer with Jimmy Savile… I mean who advised the Prime Minister to say this? We’re better than this, we must seek to improve our standards and rise above where we are today.”
He added: “I don’t think the Prime Minister realises how worried colleagues are in every corner of the party, backbenchers and ministers alike, that this is all only going one way and will invariably slide towards a very ugly place.
“I believe it’s time for the Prime Minister to take a grip of this; he himself should call a vote of confidence rather than waiting for the inevitable 54 letters to be eventually submitted.
“It’s time to resolve this completely so the party can get back to governing, and, yes, I know the next question you will ask, I will be submitting my letter today to the 1922 Committee.”
Earlier, Northern Ireland Select Committee chairman and North Dorset Tory MP Simon Hoare also called for the Jimmy Savile remarks to be withdrawn.
Mr Ellwood is the 11th Tory MP to publicly call for Boris Johnson to resign.
Last night Peter Aldous became the tenth, urging the PM to go "in the best interests of the country" after a "great deal of soul-searching".
Mr Aldous has sent a letter of no confidence to the 1922 Committee.
Mr Johnson faced this call to quit as he travelled to Ukraine to hold crisis talks on how the UK will bolster the nation's defence against potential Russian "aggression".
In the Commons on Monday, Tory grandee Andrew Mitchell told the PM he no longer "enjoys my support".
Expressing his concerns, Mr Aldous said on Twitter : "After a great deal of soul-searching, I have reached the conclusion that the Prime Minister should resign.
"It is clear that he has no intention of doing so and I have therefore written to the Chairman of the 1922 Committee of Backbench Conservative MPs, advising him that. have no confidence in the Prime Minister as Leader of the Conservative Party.
"I have never taken such action before and had hoped that I would not be put in such an invidious position.
"Whilst I am conscious that others will disagree with me, I believe that this is in the best interests of the country, the Government and the Conservative Party."
When asked if the PM was worried about another Tory MP calling for his resignation, the Prime Minister's official spokesman said: “You have seen the Prime Minister seek to address the concerns of MPs in the House for a number of hours yesterday, so I can point you back to those comments.
“Obviously at the moment he is in Ukraine, focused on the challenges there.”
