A Tory MP who asked if the Prime Minister thought he is a "fool" for following Covid rules has sent a letter of no confidence.
Aaron Bell MP for Newcastle-under-Lyme said Boris Johnson's position is “untenable” as partygate has created a “breach of trust".
Mr Bell, who was elected in 2019, said he wrote his letter on January 12, after the PM apologised in the Commons for attending a Downing Street lockdown party.
He has since struggled to "square the Prime Minister's words from the despatch box with his previous statements to the house before Christmas".
Mr Johnson apologised in the Commons and told MPs: "When I went into that garden just after six on 20 May 2020, to thank groups of staff before going back into my office 25 minutes later to continue working, I believed implicitly that this was a work event."
But Mr Bell clearly was still struggling to make sense of his own personal grief as this week he expressed the difficulty of attending his grandmother's funeral without being able to hug his parents or siblings.
Mr Bell told MPs: "I didn’t hug my siblings, I didn’t hug my parents, I gave the eulogy and then afterwards I didn’t even go to her house for a cup of tea.
"I drove back three hours from Kent to Staffordshire. Does the Prime Minister think I’m a fool?”
The Prime Minister struggled to respond to his question and said: "No Mr Speaker and I want to thank my honourable friend and say how deeply I sympathise with him and his family for their loss.
"I'm sorry for the judgments made by me or No 10 and I ask him respectfully to look at what Sue Gray has said and also respectfully to wait for the report."
The Prime Minister faces a "drip, drip" of disillusioned Tory MPs calling for him to quit until Scotland Yard has completed its 'Partygate' probe.
Three more Tories have submitted letters of no confidence in Mr Johnson earlier this week - in just one day.
It means the number of letters required to trigger a no confidence vote is creeping up towards the 54 threshold.
On Wednesday three Tory MPs expressed their lack of confidence in the PM and called for him to go.
If things could not get any worse on Thursday, Mr Johnson lost his most loyal aide who struggled to understand why he didn't apologise for accusing Keir Starmer of not prosecuting Jimmy Savile - a false accusation.