Boris Johnson was battling on after a senior Tory demanded “in the name of God, go” and a Conservative MP defected to Labour over allegations of rule-breaking parties in Downing Street.

Former Brexit secretary David Davis called for the Prime Minister’s resignation in a Commons intervention on Wednesday before later warning the party faces “dying a death of 1,000 cuts” if they do not act swiftly to oust him.

Minutes before Prime Minister’s Questions, Bury South MP Christian Wakeford dramatically switched sides, refusing to “defend the indefensible” over alleged breaches of Covid rules.

But Mr Johnson was said to have been handed a fragile reprieve by some colleagues considering forcing a no confidence vote until they hear the result of senior civil servant Sue Gray’s inquiry into events in No 10 during restrictions.

He had been holding talks with backbench MPs to shore up support and prevent the 54 letters being sent to Sir Graham Brady, the chair of the 1922 Committee of Conservatives, that are required to trigger a vote of no confidence.

With Mr Wakeford facing anger from former colleagues on the Tory benches, some suspected he had temporarily galvanised support for Mr Johnson ahead of Ms Gray’s report, which is now expected next week.

No 10 said Mr Johnson will fight any no-confidence vote launched against him and insisted he expects to fight the next general election.

The Prime Minister went into the Commons with his premiership on life support, as a group of Tories who won their seats in the 2019 election landslide appeared to have lost faith in their boss.

The anger from a former minister first elected in 1987 and Mr Wakeford, elected to the so-called Red Wall seat of Bury South two years ago, showed the breadth of the fury in the party.

In an interview with the Daily Telegraph, Mr Davis said: “The party is going to have to make a decision or we face dying a death of 1,000 cuts.”

The Prime Minister will appear to be “shifting the blame” if he fires staff after Ms Gray delivers her inquiry into events held at No 10 during Covid restrictions, the Haltemprice and Howden MP said.

Then there will be the “crises” of rising energy bills and the National Insurance hike being compounded by the “disorganisation” at No 10, which could trigger a vote of no confidence at Christmas, meaning a “year of agony”, he continued.

“That’s the worst outcome, particularly for the 2019 and 2017 and 2015 intake – that, slice by slice by slice, this carries on and we bump along at minus whatever and, even worse, we create policies to try to paper over it.”

Commons Leader Jacob Rees-Mogg sought to downplay Mr Davis’s intervention, describing the former minister as having “always been something of a lone wolf”.

“No-one would call David a lightweight, he’s a very serious political figure, but his comments today were too theatrical,” he added.

Mr Wakeford, who was elected in 2019 with a majority of just 402 votes, accused Mr Johnson of being “incapable of offering the leadership and government this country deserves” as he switched sides.

Following a joint media appearance with Labour leader Sir Keir Starmer, Mr Wakeford said the Tories are “a party trying to defend the indefensible” as he explained his defection.

A Labour spokesman said the party had been in talks with Mr Wakeford for “some time” and would welcome an election, after Mr Johnson said the Tories would win back Bury South.

He declined to say whether there are more Conservative MPs considering defecting, while the Prime Minister’s press secretary said she was not aware of any.

Transport Secretary Grant Shapps suggested there should now be a by-election in the constituency, telling ITV’s Peston Mr Wakeford “should front up to his constituents”.

In the Commons, Mr Johnson apologised again for the partygate saga, which threatens to be the death knell for his time as Prime Minister.

But he said it was for Ms Gray’s inquiry “to come forward with an explanation of what happened”, while facing particular scrutiny over the “bring your own booze” party in the No 10 garden on May 20 2020 that he has admitted attending despite the lockdown.

The PM has insisted “nobody told me that what we were doing was against the rules” and he believed he was attending a work event.

But former aide Dominic Cummings alleged Mr Johnson was aware of the event in advance and was warned it broke the rules in place at the time.

The May 20 event is one of many subject to Ms Gray’s inquiry, and Tory MPs were urged by ministers to wait for her report before deciding whether to move against the Prime Minister.

Health Secretary Sajid Javid told a Downing Street press conference he “fully supports the Prime Minister” as awaits the Gray report.

Mr Javid, who ran against Mr Johnson for the leadership in 2019, did not rule out another bid in future, saying: “We have a leader. We have a Prime Minister.”

During a chaotic session PMQs, Mr Davis said he had spent weeks defending Mr Johnson 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,” Mr Davis said.

“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: You have sat too long here for any good you have been doing. In the name of God, go.”

Seven Tory MPs have publicly called for Mr Johnson to go, far short of the 54 required to submit letters of no confidence to the backbench 1922 Committee.

The number would have been eight but Mr Wakeford’s defection means the tally is unchanged.