Theresa May has issued a grovelling apology for her catastrophic election campaign, admitting to a meeting of Tory MPs: “I'm the person who got us into this mess."

The mea culpa made to a packed room of Conservative MPs saw the Prime Minister accused of running a “Laurel and Hardy government”, as she acknowledged a string of mistakes that squandered her party’s grip on power.

The consequences of Ms May’s election gamble were further underlined on Monday as her administration’s ability to pass a Queen’s Speech – the most basic test of a government’s credibility – was cast into doubt.

The most senior minister in her cabinet admitted the monarch’s ceremonial speech could be delayed if Ms May fails to convince the Northern Irish Democratic Unionist Party (DUP) to back her.

It also emerged that Brexit talks may be set back as a result of the chaos in British politics, decreasing chances of a withdrawal deal by 2019.

The crunch meeting of the 1922 Committee – representing the voice of Tory backbenchers – lasted longer than usual, for more than an hour while Ms May was interrogated by MPs.

As she marched to the door of the Commons committee room, she refused to speak to reporters, one of whom shouted: “Are you nervous Prime Minister?”

On entering there were some cheers and desk banging, but it was far from the rapturous greeting she had last year on taking office.

UK Election Day 2017 Show all 38 1 /38 UK Election Day 2017 UK Election Day 2017 Door of Number 10 Downing Street is seen on the morning after Britain's election in London REUTERS UK Election Day 2017 Labour leader Jeremy Corbyn leaves his home in north London after he called on the Prime Minister to resign, saying she should "go and make way for a government that is truly representative of this country" PA UK Election Day 2017 Shadow Chancellor John McDonnell arrives at Labour Headquarters on June 9, 2017 in London, England. After a snap election was called by Prime Minister Theresa May the United Kingdom went to the polls yesterday. 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The event was so packed that one Conservative peer had to be turned away. Those inside described conditions as “swelteringly hot” and a “sauna”.

Addressing MPs, she said: “I’m the person who got us into this mess – and I’m the one who’s going to get us out of it.”

People there said she uttered the word “sorry” repeatedly, and as the meeting dragged on was asked if she had time to continue, replying: “No, no, I’ve got time – I said I’d changed.”

One MP told The Independent: “She said she had been stuffing envelopes for the party since she was 12 years old and that she would continue to serve as long as we wanted her to.”

The acknowledgment that her own backbenchers have power to make or break her, appears to have been a key turning point as she went on to pledge more involvement in decision-making for her backbenchers.

Election fallout: Queen's speech could be delayed

Ann-Marie Trevelyan, a Conservative MP in the North East, said the Prime Minister had given a full “mea culpa”, adding: “She said, ‘It’s my fault – I take full responsibility.’

“She had clearly considered deeply, over the weekend, whether she should continue and now felt absolutely that she should.

“She came to us to say that she would continue as long as we wanted her to – which is exactly what we wanted her to say. The room really warmed up after that.”

Another MP said the apology had been “cathartic” for MPs, confirming they wanted Ms May to stay: “If the mood had flickered immediately after the election, then it is behind her again now.”

Ms May also signalled she could be willing to soften her approach on Brexit as she pledged to listen to “all the voices” in the party on the issue, following calls to adopt a more ‘jobs first’ approach from both members of her cabinet and the back benches.

Shortly after she did, Mid Norfolk MP George Freeman tweeted: “This is a moment for Cabinet to drop Hard Brexit message.”

The scene is now set for another damaging and destabilising Tory row over the European Union, with Leavers demanding Ms May maintain her tough stance, but others pointing out that her approach had been rejected by the electorate.

Scottish Tory leader Ruth Davidson – who came to Downing Street for talks today – and Chancellor Philip Hammond have both told Ms May she must put the economy, as opposed to immigration, first in Brexit negotiations.

Ruth Davidson arrives for cabinet meeting

MPs also said the Prime Minister had given the necessary reassurance on the consequences of a tie-up with the DUP at the 1922 meeting, promising it would not threaten the party’s stance on gay rights or the Northern Ireland peace process.

Another Tory MP said there was no discussion at the meeting of how long Ms May would remain in post, adding: “She’s won, she’s got to be PM.”

But despite her efforts to placate her own benches, the difficulty of Ms May’s position was further underlined as Damian Green, the First Secretary of State, admitted the Queen’s Speech may have to be put back.

The ceremonial speech marks the publication of a government’s legislative agenda, and an inability to win a vote approving it means the administration cannot function.

With the speech pencilled in for Monday, Mr Green confirmed there could be a delay while an agreement is sought with the DUP, saying: “Obviously, until we have that we can’t agree the final details of the Queen's Speech.”

Brexit Secretary David Davis admitted that the Tories’ manifesto programme would have to be “pruned”, with a string of policies set to be dumped – likely including the social care plan, proposals to ditch the triple-lock on pensions and to means-test the winter fuel payment.

He also signalled that discussions on the UK’s exit from the EU may not start on 19 June as anticipated, but hoped they would begin sometime the same week.

The Prime Minister is set to meet the leader of the DUP Arlene Foster on Tuesday, to plead for the party’s backing in the Commons, something which would give her a working majority.

Ms Foster declined to give details of what she termed had so far been a “positive engagement with the Conservative Party”.

She said she would be travelling to London late on Monday for discussions with her team of ten DUP MPs ahead of her meeting at No 10.

But Liberal Democrat leader Tim Farron said the events of the day showed “the complete chaos [Ms May] has left the country in”.

He went on: “Theresa May certainly did get us into this mess. She promised strong and stable, but we’ve ended up with Laurel and Hardy government.

“If she can’t even properly organise a Queen’s Speech, how can she possibly run the country for five years?”