Boris Johnson on Wednesday night refused to quit and instead sacked Michael Gove, despite being confronted by Cabinet ministers, mass frontbench resignations and the threat of another leadership vote.
The Prime Minister was on the brink of being ousted as more frontbench walkouts took the total of Tory MPs quitting official posts over the past two days beyond 40.
In one-on-one meetings with Mr Johnson on Wednesday night, a string of Cabinet ministers personally told him he had lost the support of his party and should consider resigning.
The Telegraph can reveal that the government Whips Office has calculated that Mr Johnson would win the support of just 65 Tory MPs in a new confidence vote, from a total of almost 360.
But he rejected the Cabinet pressure to go, insisting there would be three months of “chaos” if he went, while the Tories picked a successor before a likely election defeat to Labour.
Anger was building on Wednesday night among Tory critics of Mr Johnson. Sir Bob Neill, the chairman of the justice committee, said: “Our country is being made a laughing stock by one person’s obsessive selfishness.”
Tobias Ellwood, the chairman of the defence committee, said: “We have a patriotic duty to conclude this.”
Simon Hart, the Welsh Secretary, resigned on Wednesday night over Mr Johnson's refusal to heed Cabinet warnings and step down.
Meanwhile the leadership race to succeed the Prime Minister broke into the open late Wednesday as Suella Braverman, the Attorney General, declared her candidacy.
Ms Braverman announced her bid to become the next leader live on ITV News, vowing tax cuts and calling on Mr Johnson to go - though she did not quit the Cabinet.
The Prime Minister sacked Mr Gove, the Communities Secretary, in a phone call at around 9pm on Wednesday. Mr Gove was accused by Downing Street of leaking to the press that he had urged him to step down.
A Johnson ally said of Mr Gove: “He has just always been treacherous, disloyal, self-obsessed, untrustworthy – pick whichever you like.” He was also likened to a “snake” by supporters of Mr Johnson.
The ally insisted there would be no “lectern moment” soon, declaring that Mr Johnson was planning an economic reset speech that would promise tax cuts and deregulation.
The Prime Minister’s message to Tory rebels seeking his removal was “sober up, smell the coffee and wake up”, warning that Labour could claim Number 10 with the SNP and the UK could break up if he goes, said the ally.
The point-blank refusal to accept the pleas of his own Cabinet ministers to quit was a stark difference to Margaret Thatcher, who agreed to step down in 1990 after Cabinet pressure.
The stand-off was unlike anything in modern British political history, with Theresa May and Tony Blair previously having agreed to leave office after growing criticism within their party.
Priti Patel, the Home Secretary, Nadhim Zahawi, the new Chancellor, and Chris Heaton-Harris, the Chief Whip, were among the Cabinet figures who told Mr Johnson he had lost the support of his party. More than half a dozen Cabinet figures made that argument.
By Wednesday night, 45 Tory MPs had resigned from official positions. That included 19 government ministers quitting, 16 on Wednesday.
Sir Graham Brady, the 1922 Committee chairman, on Wednesday told Mr Johnson a second vote on his leadership could happen as early as next week, with a new executive voted in on Monday and free to change the leadership rules on Tuesday.
A Johnson ally told The Telegraph: “There will be no lectern moment. The much-billed [Cabinet ministers] delegation of doom was not as doom-ladened as portrayed.
“The Prime Minister has been saying the choice is not ‘me or not me’. The alternative is pressing the button for three months of chaos as the party tears itself apart with no mandate. Labour will immediately demand an election, which this party will lose given the ‘coalition of chaos’ between Labour and the SNP, and [there will be the] possible break-up of Britain.”
The source summarised the message to Tory rebels as “stop thinking ‘this is Boris or no Boris’, or ‘topple Boris and this is all over’. Stick with this PM and a new Chancellor with a new economic programme. That is what is called for”.
Not everyone in the Cabinet turned on Mr Johnson on Wednesday. Both Jacob Rees-Mogg, the Brexit minister, and Nadine Dorries, the Culture Secretary – two of Mr Johnson’s most loyal supporters – rushed to Number 10 to urge him to stay.
Liz Truss, the Foreign Secretary, was flying to Indonesia and Ben Wallace, the Defence Secretary, was travelling by train. Figures close to both Cabinet ministers declined to say whether they had privately urged the Prime Minister to go.
Mr Zahawi also did not quit despite warning the Prime Minister of the perilous political position. He was back in the Treasury and working with Number 10 on a speech on a “new economic plan” that will include tax cuts.
Mr Gove did tell Mr Johnson to resign. He held a five-minute one-on-one meeting with him on Wednesday morning and urged him to quit on his own terms before it was too late.
Downing Street critics pointed the finger at Mr Gove after four figures in his department quit on Wednesday afternoon, fuelling calls for Mr Johnson to go. But an ally denied he was plotting and said he would “100 per cent” not stand to be Tory leader if there was a contest.
Throughout Wednesday, a succession of ministers and parliamentary private secretaries resigned, many tweeting letters with excoriating views of Mr Johnson.
He also had to endure two Tory MPs calling for him to go during Prime Minister’s Questions, after which he sat with his arms crossed as Sajid Javid, his former health secretary who quit on Tuesday, gave a speech in which he called for the Cabinet to act.
Yet during a two-hour appearance before the liaison committee, Mr Johnson declared that he was having a “terrific” week and insisted his Government was pushing ahead with “ever-increasing energy”.
There were signs of the mass resignations making government difficult, with planned scrutiny of a piece of legislation with MPs cancelled because the minister in question had quit. On Wednesday night it was unclear how long the stand-off would continue, with scores of Tory MPs despairing about the situation.
If Mr Johnson remains in post by early next week, rebels predicted that the 1922 Committee would force a second leadership vote to oust him that way.