Liz Truss dramatically quit today, admitting defeat following crisis talks with Tory chiefs in Downing Street and with MPs in open insurrection.

After just 44 disastrous days in No10, the PM took to a lectern outside the famous black door to confirm her departure, sealing her fate as the shortest-serving premier in modern political history.

Revealing she had informed the King of her decision, she said: ‘I cannot deliver on the mandate…. I will remain as PM until a successor has been chosen.’

Ms Truss – who insisted she was a ‘fighter not a quitter’ barely 24 hours ago – said the Tory leadership contest will be completed over the next week. Giving her valedictory statement, she was watched by husband Hugh.

Attention immediately turns to the leadership battle – with Jeremy Hunt ruling himself out within minutes. However, Penny Mordaunt’s ‘grassroots’ campaign Twitter account has already fired up, while Rishi Sunak and Suella Braverman are thought likely to run. Boris Johnson, currently on holiday in the Caribbean, could bid for a shock return just six weeks after he left office.

Conservative 1922 Committee chair Sir Graham Brady told journalists in Westminster that a replacement should be in place by October 28, in time for the Halloween Budget.  

The bombshelll news follows a week of carnage that saw a bewildering array of U-turns on the mini-Budget, the Chancellor and Home Secretary quit, confusion over whether the Chief Whip had followed her out of the door and MPs wrestling in Commons voting lobbies.

Ms Truss held crisis talks with 1922 chair Graham Brady, deputy PM Therese Coffey and Tory chair Jake Berry in the building earlier, as they delivered grim message about the mood of the party. 

A series of previously-loyal MPs joined calls for her to go this morning. Even supportive Cabinet ministers had been conceding the situation is ‘terminal’. Transport Secretary Anne-Marie Trevelyan was sent out to prop up the PM this morning, but would only say that ‘at the moment’ she believes Ms Truss will lead the Tories into the next election.

The main obstacle to removing Ms Truss over recent days was the lack of consensus on who should take over and what the process should be, with little appetite for a drawn-out contest. Nadine Dorries has warned the only person who would be acceptable in a ‘coronation’ is Mr Johnson.

One idea being pushed by influential Tories is that MPs vote on a successor, but there is a very high threshold of nominations to get on the ballot.

The 1922 committee could ask candidates to agree that they will step aside if they are not in pole position when the field is whittled down to a final two. That would avoid the need for a run-off vote of the entire party membership.

A source said of the blueprint, ‘That has been put to someone very senior in the party, very, very senior.’  

Events accelerated after another bout of madness at Westminster yesterday culminated in stories of tears and tantrums in Parliament, with Ms Truss allegedly engaging in a shouting match with her own enforcers.

Deputy PM Therese Coffey was accused of ‘manhandling’ Tory MPs to vote against a Labour motion that could have killed the government’s plans to resume fracking – something she denies.

The premier tried to force the issue by declaring that it was a matter of confidence, meaning a defeat the would have collapsed the government. But at the end of the debate a minister declared that it was not in fact a confidence vote – triggering fury from Chief Whip Wendy Morton and her deputy Craig Whittaker.

Other whips told MPs they had resigned, but after three hours of silence and frantic wrangling behind the scenes Downing Street announced they were still in post. A 1.33am statement then made clear that it had been a confidence vote, warning that around 30 MPs who abstained will be disciplined.

However, in another twist this morning, Ms Trevelyan said that it had not been a confidence vote.

The PM lost her second Cabinet heavyweight in five days after Suella Braverman resigned as Home Secretary, admitting using of her personal email to campaign against the government’s own immigration policy – but also hit out at Ms Truss for ditching key policies, suggesting she should also quit for ‘mistakes’. 

Tory backbencher Gary Streeter said he believes that Ms Truss must go, but warned that even the ‘Angel Gabriel’ will struggle to lead the party because it lacks ‘discipline, mutual respect and teamwork’. Fellow Conservative Sheryl Murray said: ‘I had high hopes for Liz Truss but after what happened last night her position has become untenable and I have submitted a letter to Sir Graham Brady.’

Hendon MP Matthew Offord told the Evening Standard said Ms Truss needs to make a ‘dignified exit’. ‘I can’t see the situation being sustainable. She does need to sit down and discuss it with her Cabinet and with others to manage some kind of dignified exit.’

Crawley MP Henry Smith told Times Radio that the Conservatives ‘cannot delay’ getting rid of the premier. Tory Jill Mortimer, who shocked Labour by winning the Hartlepool by-election just last year, shared an image of her letter of no confidence on Facebook.

She added, ‘Yesterday, I tried to get called in PMQs to ask Liz Truss for an assurance of support for our town and our promises.

‘Sadly I was not called and the deteriorating situation throughout the day left me with no choice but to submit a letter of no confidence in the Prime Minister to Sir Graham Brady.’

Senior MP Simon Hoare told BBC Radio 4’s Today programme: ‘I’m a glass half full sort of person. Can the ship be turned around? Yes. But I think there’s about 12 hours to do it.

‘I think today and tomorrow are crunch days. I have never known – OK, I’ve only been an MP for seven years – but a growing sense of pessimism in all wings of the Tory party.’

In a rant during an interview that was retweeted by colleagues, veteran Conservative MP Charles Walker said: ‘I think it’s a shambles and a disgrace. I think it is utterly appalling. I am livid.’

Last night Conservative MPs were confident that between 50 and 100 letters of no confidence had been

submitted to Sir Graham, despite current rules stating the committee cannot hold a vote of confidence in Liz Truss for a year after her appointment.

And in another hit for the PM, Tory MP William Wragg confirmed within the House of Commons that he was one of those who has submitted a letter. There are now at least 14 Tory MPs on the record who have said Ms Truss can’t continue.

Recent polling shows Ms Truss has lower approval ratings than both Boris Johnson and Jeremy Corbyn at any time during their time as leader of their parties.

After the government declared yesterday morning that the vote on banning fracking was an issue of confidence and all Conservative MPs had to vote against the motion, raucous scenes ensued after Climate Minister Graham Stuart at the last minute told the Commons it was not a confidence motion after all.

Deputy chief whip Craig Whittaker had written to Conservatives telling them it is a ‘100 per cent hard 3 line whip!’

‘We cannot, under any circumstances, let the Labour Party take control of the order paper and put through their own legislation and whatever other bits of legislation they desire,’ he said.

‘We are voting NO and I reiterate this is a hard 3 line whip with all slips withdrawn.’

The last-minute withdrawal of this caused Chief Whip Wendy Morton to storm out of the Chamber, before reportedly publicly declaring ‘I am no longer the Chief Whip’ while standing just a metre away from the PM.

While Tory MPs were originally telling reporters that both the Chief Whip and her Deputy, Craig Whittaker, had quit their roles and handed in resignation letters, confusion soon intensified after it was reported Liz Truss followed Ms Morton and pulled her into an intense meeting to prevent her quitting. 

For several hours, no-one from the government could confirm or deny the claims that both the top whips had resigned. When pressed on issue, Business Minister Jacob Rees-Mogg said he was ‘not clear’ what the ‘situation’ with the whips was.

By 9pm, Ms Coffey was telling reporters outside the Carlton Club – where with exquisite timing the entire Cabinet was due to attend a dinner for the centenary of the agreement that sunk Lloyd George’s government – that Ms Morton had won a ‘great victory’ by defeating the Labour motion.

No10 confirmed at 9.49pm that the pair were indeed remaining in post.  The Carlton Club bash was originally due to be black tie, but was downgraded to avoid pix of the Cabinet looking too decadent on day huge inflation figures were unveiled.

• A Daily Mail report