Boris Johnson is facing the largest threat to his premiership after he was fined for breaking lockdown rules by attending his "birthday party" in the Cabinet room in June 2020.
The latest development in the 'partygate' scandal has resulted in renewed calls for the Prime Minister to step down from his role.
Nigel Mills, the Tory MP for Amber Valley, became the first backbencher to call for Mr Johnson to quit since the Met Police announced that, along with Carrie Johnson and Rishi Sunak, he would receive a fixed penalty noticed (FPN).
Mr Mills joins several Conservative MPs who had previously publicly called on the Prime Minister to quit. But a number of Cabinet ministers have also rallied behind the Prime Minister to publicly shore up his support.
Below is the full list of Tory MPs who have called on Mr Johnson to stand down so far:
Since the Prime Minister received a FPN
1. Nigel Mills - MP for Amber Valley
A Tory MP broke ranks to become the first Conservative backbencher to call for Boris Johnson to quit since the Prime Minister was fined over the "partygate" scandal.
Nigel Mills, the Tory MP for Amber Valley, said on Apr 13 that he no longer believes Mr Johnson's position as Prime Minister is "tenable".
Speaking to BBC Radio Derby, Mr Mills said: "In all conscience I don’t think a prime minister can survive or should survive breaking the rules he put in place and he was on the TV every few nights, reminding us all that we should observe.
“We have to have higher standards than that of people at the top. He has been fined, I don’t think his position is tenable, in my view.”
2. Craig Whittaker
Mr Whittaker, the MP for Calder Valley who has previously been a staunch supporter of the Prime Minister, called for him to resign during a Facebook question-and-answer session.
"I not only think that the Prime Minister should resign but I also think that Rishi Sunak should resign as well", he said. "Through this whole process it hasn't been particularly clear that the Prime Minister broke any rules until of course he's been issued with a fixed penalty notice this week."
However, Mr Whittaker confirmed he would not submit a letter of no-confidence to the 1922 Committee as he expected that Mr Johnson would win a vote of Tory MPs.
3. Karen Bradley
Ms Bradley, a former Northern Ireland Secretary and the MP for Staffordshire Moorlands, told Stoke-on-Trent Live: "I will spend the next few days consulting my constituents and will decide on what action to take after listening to them.
"But I do wish to make it clear that if I had been a minister found to have broken the laws that I passed, I would be tendering my resignation now."
4. Dr Neil Hudson
Dr Hudson, the Tory MP for Penrith and the Borders, maintained his position "that I categorically will not defend the indefensible".
"Destabilising the UK Government would undermine international efforts to support the Ukrainian people and bring the despicable Russian invasion to an end," he said in a statement.
"I will therefore be looking to the Prime Minister to show the statesmanship he has been showing with Ukraine, and outline a timetable and process for an orderly transition to a leadership election as soon as the international situation permits."
5. Mark Harper
Mark Harper, the Tory former chief whip, called on Boris Johnson to resign and said the Prime Minister was no longer "worthy of the great office that he holds".
Mr Johnson told the House of Commons that he apologised "unreservedly" after he was fined over the "partygate" scandal.
But his apology was not enough to win over Mr Harper who told the Prime Minister he should now quit 10 Downing Street.
He later revealed on Twitter he had submitted a letter to the 1922 Committee of backbench Conservatives calling for a no-confidence vote in Mr Johnson.
My letter to @SirGrahamBrady. pic.twitter.com/cy7MEa3QyL
— Mark Harper (@Mark_J_Harper) April 19, 2022
Speaking in the Commons, Mr Harper said: "I regret to say that we have a Prime Minister who broke the laws that he told the country they had to follow, hasn't been straightforward about it and is now going to ask the decent men and women on these benches to defend what I think is indefensible."
Following initial 'partygate' reports
1. William Wragg - MP for Hazel Grove and Vice-Chairman of the 1922 Committee
Mr Wragg suggested Mr Johnson should take the decision to resign himself. He told the BBC that it was "a tragedy things have come to pass in this way", adding: "Unfortunately, I wasn't reassured. I fear this is simply going to be a continuing distraction to the good governance of the country."
He said it would be "preferable" for Mr Johnson to offer his resignation himself as MPs were "tired" and "frankly worn out of defending what is invariably indefensible".
"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. I think it is for the Conservative Party, if not the Prime Minister, in fact, to make that decision, and to realise what is in the best interest, so that we can move forward both as a party and a country," he said.
He added that "no doubt the Prime Minister is reflecting deeply on what has happened, but I cannot in all sincerity see a way where these issues go away".
"It is deeply unfortunate, but I'm afraid it is... the inevitable conclusion is the only way to do that is with a change," he said.
2. David Davis - MP for Haltemprice and Howden
David Davis, the former Brexit Secretary, called on the Prime Minister to resign in a stinging rebuke during Prime Minister's Questions on Wednesday.
Mr Davis told Mr Johnson he had spent weeks defending him from "angry constituents", including by reminding them of the "successes of Brexit".
"I expect my leaders to shoulder the responsibility for the actions they take. Yesterday he did the opposite of that. So, I will remind him of a quotation which may be familiar to his ear: Leopold Amery to Neville Chamberlain," he said.
"You have sat too long here for any good you have been doing. In the name of God, go."
3. Caroline Nokes - MP Romsey and Southampton North
Ms Nokes was the fourth Tory MP to call for Mr Johnson to resign, telling ITV's Peston that the Prime Minister had "put himself in an impossible position".
"The message I've had from my constituents is they feel let down they feel disappointed, and I know how hard they worked through the pandemic to abide by the rules," she said.
"They now see that the Prime Minister wasn't in it together with them, that the rules were being broken in Downing Street, and that's very serious."
Ms Nokes said she recognised Mr Johnson "did a fantastic job" at the 2019 election, but she said: "Now regretfully, he looks like a liability, and I think he either goes now, or he goes in three years' time at a general election, and it's up to the party to decide which way around that's going to be. I know my thoughts are is that he's damaging us now."
4. Tim Loughton - MP for East Worthing
Tim Loughton, a former minister, publicly called for Mr Johnson to quit and said: "I am very angry too."
"Frankly the issue for me is not how many sausage rolls or glasses of Prosecco the Prime Minister actually consumed.
"The reason for my conclusion in calling for him to stand down is the way that he has handled the mounting revelations in the last few weeks."
5. Aaron Bell - MP for Newcastle-under-Lyme
Aaron Bell, who was elected in December 2019 as part of Mr Johnson's landslide election victory, told the Sunday Times he had submitted a letter of no confidence, and on Feb 4 issued a statement confirming his.
He said that he was "profoundly disappointed that it has come to this" after backing the Prime Minister through Brexit, the vaccine roll-out and levelling up.
Mr Bell said that the events in Downing Street and "the manner in which they were handled" now meant that Mr Johnson's position was "untenable".
As the Prime Minister addressed MPs about Sue Gray's update on alleged breaches of lockdown rules at Downing Street and across Government, Mr Bell told MPs: "It seems a lot of people attended events in May 2020 - the one I recall attending was my grandmother's funeral.
"I drove for three hours from Staffordshire to Kent, there were only 10 at the funeral, many people who loved her had to watch online. 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 cup of tea. I drove back three hours from Kent to Staffordshire. Does the Prime Minister think I'm a fool?"
Mr Bell said he wrote his letter after Prime Minister's Questions on January 12, "when I could not square the Prime Minister's words from the despatch box with his previous statements to the House before Christmas. Subsequently I have also struggled to reconcile assurances given directly to me with the implication of Sue Gray's interim findings."
6. Peter Aldous - MP for Waveney
In a Twitter thread on Weds, Feb 1, Mr Aldous wrote: "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 I 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."
7. Tobias Ellwood - chairman of the defence select committee and MP for Bournemouth East
A vote of no confidence in Boris Johnson is now "inevitable", Tobias Ellwood has said as he confirmed he will submit a letter to the 1922 Committee later today.
Mr Ellwood told Sky News the ongoing row over alleged parties at Downing Street was "horrible" for Conservative MPs to continue to have to defend to the British public, and attacked "rushed policy announcements" from No 10.
Conservative MP Tobias Ellwood says Boris Johnson should call a vote of confidence himself, adding that he will be submitting his own letter to the 1922 Committee today.
— Sky News (@SkyNews) February 2, 2022
Latest: https://t.co/k4V3ROya7i
📺 Sky 501, Virgin 602, Freeview 233 and YouTube pic.twitter.com/8tnzzkExWD
"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," Mr Ellwood told Sky News.
"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 on with governing.
"And yes, I know the next question you'll ask, I will be submitting my letter today to the 1922 Committee."
He also criticised Boris Johnson's claims about Sir Keir Starmer in relation to Jimmy Savile on Monday, adding: "We must seek to improve our standards."
8. Anthony Mangnall - MP for Totnes
On Weds, Feb 2, Anthony Mangnall confirmed he had submitted a letter of no confidence in the Prime Minister.
"Standards in public life matter," he wrote on social media in light of Mr Johnson doubling down on his claims about Sir Keir and Savile at Prime Minister's Questions.
"At this time I can no longer support the PM.
"His actions and mistruths are overshadowing the extraordinary work of so many excellent ministers and colleagues. I have submitted a letter of no confidence."
9. Sir Gary Streeter - MP for South West Devon
Sir Gary Streeter became the third Conservative MP to submit a letter of no confidence in Boris Johnson on Weds, Feb 2 after the update issued by Sue Gray.
"I cannot reconcile the pain and sacrifice of the vast majority of the British public during lockdown with the attitude and activities of those working in Downing Street," wrote Sir Gary, who has been an MP since 1992.
"Accordingly, I have now submitted a letter seeking a motion of no confidence in the Prime Minister. I have not come to this decision lightly. It is not my intention to say any more about this matter. I will focus on serving the residents of South West Devon."
10. Sir Nick Gibb - MP for Bognor Regis and Littlehampton
Writing for The Telegraph, Sir Nick, a former minister, said: "We need to face up to hard truths. To restore trust, we need to change the Prime Minister."
He added: "My constituents are furious about the double standards – imposing harsh and, to my mind, necessary restrictions as we and the world sought to defend ourselves against this new and deadly virus, while at the same time flagrantly disregarding those rules within the fortress of Downing Street."
Christian Wakeford - has defected to Labour
Christian Wakeford, the MP for Bury South, told Yahoo News on Tues, Jan 18 that he had called on the Prime Minister to resign and confirmed reports of a "pork pie plot" among the 2019 intake of MPs to oust their party leader.
Mr Wakeford then shocked the Commons shortly before midday the following day (Jan 19) as he confirmed reports he had defected to the Labour Party.
The Tories who called for Johnson to go... but changed their minds
Douglas Ross, Leader of the Scottish Tories
"I said if the Prime Minister attended this gathering, event in Downing Street on May 20 2020, he could not continue as Prime Minister so, regretfully, I have to say his position is no longer tenable," Mr Ross said earlier in February.
"There was one simple question to answer yesterday, indeed, from Monday night when we saw this invitation which was to more than 100 people asking them to join others in the Downing Street garden and bring their own booze. If the Prime Minister was there, and he accepted today that he was, then I felt he could not continue."
But the following month, he withdrew his demand that Boris Johnson resigns over "partygate" and invited him to the Scottish Tory conference later that month in a boost to the PM.
Sir Roger Gale - MP for North Thanet
Sir Roger, 78, has been the Conservative MP for North Thanet since 1983.
"I'm sorry, you don't have 'bring a bottle' work events in Downing Street, so far as I'm aware," he said on Feb 1. "And you don't have 'bring a bottle' work events that are advertised or invited by the Prime Minister's private secretary.
"I think the time has come for either the Prime Minister to go with dignity as his choice, or for the 1922 Committee to intervene."
But on Apr 13, the Tory MP for North Thanet, suggested the UK cannot afford to have a "lame duck" prime minister while the Ukraine crisis is ongoing as he cautioned against ousting Boris Johnson now.
Andrew Bridgen - MP for North West Leicestershire
Mr Bridgen, who backed Mr Johnson to be leader in June 2019, said in February that he should stand aside within three months and warned of "a moral vacuum at the heart of our Government" in the wake of the "partygate" revelations, adding: "Sadly, the Prime Minister's position has become untenable."
But he then publicly withdrew his letter of no confidence at a Telegraph event, citing the Ukraine crisis - in a sign that the Prime Minister’s “partygate” troubles have abated.
The Tory MSPs who echoed Douglas Ross's calls for Mr Johnson to go:
Miles Briggs, Alexander Burnett, Donald Cameron, Jackson Carlaw, Russell Findlay, Maurice Golden, Meghan Gallacher, Jamie Halcro-Johnston, Craig Hoy, Liam Kerr, Stephen Kerr, Murdo Fraser, Douglas Lumsden, Liz Smith, Sue Webber, Annie Wells, Brian Whittle, Edward Mountain, Sharon Dowey and Finlay Carson.
This article is kept updated with the latest information.