Theresa May could cling on as Prime Minister for another year while she tries to deliver Brexit, allies said.

She faced renewed calls to quit as she travelled to an emergency summit in Brussels to negotiate another delay that could last up to a year.

Former leader Iain Duncan Smith called on Mrs May to stick to her promise to resign next month.

He warned last night that she would face ‘humiliation’ if she tried to stay on against the wishes of her party and called on the Cabinet to remove her.

‘The whole thing is an utter car crash,’ he said. ‘I think the Cabinet has to have a moment with the Prime Minister and say, “This can’t go on, I’m afraid, it really can’t go on”.’

DUP leader Arlene Foster, whose party props up the Tories at Westminster, savaged Mrs May’s handling of Brexit, saying: ‘The Prime Minister should recognise that the decision to leave the EU is not the problem but rather the ham-fisted manner in which the negotiations have taken place.’

Mrs May’s future was also discussed at a meeting of the executive committee of the Tories’ 1922 Committee of backbenchers, with senior MPs calling for her to go before the European Parliament elections on May 23.

One source said: ‘The general view was she has to get a Withdrawal Agreement through and then go. However, if this goes beyond May 22, she’ll be in difficulties.’

It come after revelations that Senior Tory MPs are plotting to remove Theresa May as party leader by May 23 to install a new Prime Minister before the summer holidays in July.

Officers of the 1922 Committee - which includes all backbench Tories - want to force her out as Conservative leader but leave her in No 10 until the party contest ends.

It is not clear how Mrs May could be forced out by her party as the rules protect her from a formal contest until December after she won a confidence vote last year.

But hardline Brexiteers - including so-called Spartans Mark Francois and Andrea Jenkyns - have gone public with renewed calls for Mrs May to stand down.

The chairman of the 1922 Committee Sir Graham Brady has promised to pass on MPs' concern to Downing Street but has so far ruled out a new confidence vote.

Senior Tory MPs are plotting to remove Theresa May (pictured last night in Paris) as party leader by May 23 to install a new Prime Minister before the summer holidays in July

The chairman of the 1922 Committee Sir Graham Brady (pictured leaving Downing Street on Monday) has promised to pass on MPs' concern to Downing Street but has so far ruled out a new confidence vote

But one 1922 Committee source told the Telegraph: 'We would conclude our side of the leadership contest within two weeks and then the party and the country would get four to six weeks of decision making.

'So we then elect the new Prime Minister to come in for just before recess.'

Former Tory leader Iain Duncan Smith warned the PM must not 'drift' on as Tory leader during a new Article 50 extension today.

He told Sky News she must make way for new leader by party conference: 'My recommendation to PM is don't go to 2nd vote of confidence.

'It is almost certain that will be lost. It would be a humiliation.'

Mrs May is coming under mounting pressure from local Tory associations. One, in Clwyd South, is planning a confidence vote on April 24.

John Strafford, who runs the Campaign for Conservative Democracy, told the Telegraph the Conservative Party Board has the power to force Mrs May out.

He said: 'If the party board wants to get rid of the leader, it can do so. It can do anything it likes.'

The moves against Mrs May come as contenders to replace her swirl in a shadow contest.

Health Secretary Matt Hancock - seen by many as a dark horse in the race - yesterday warned the party needs a 'kick up the a***' to win over young voters.

Rival Penny Mordaunt, the Aid Secretary, said the UK needs ‘servant leaders, not heroes’ to lead the country out of the Brexit crisis.

Tory leadership hopeful Matt Hancock has warned the party needs a 'kick up the a***' to win over young voters as it emerged people now move from Labour to Tory aged 51

Britain's International Development Secretary Penny Mordaunt, who will fight to be Tory leader, also took part in the unofficial hustings today

Michael Gove is second favourite to win the leadership battle behind Boris Johnson

Speaking at an event in London, Mr Hancock said: 'Voting Conservative for the first time used to be when you get your first pay cheque. Now it is when you get your first winter fuel payment'.

He told the unofficial hustings today the Tories are 'finished' if they become 'only a Brexit party'.

Jacob Rees-Mogg, chairman of the European Research Group of Eurosceptic Tory MPs, who has hosted 'Back Boris' dinners at his home, paid tribute to Miss Rudd's abilities.

Asked about the prospect of Ms Rudd supporting Mr Johnson, he replied: 'Well I've always thought highly of Amber Rudd, and she is a very long-standing friend of my sister and a person of first-class capabilities.

'I happen to disagree with her on the European issue and there will come a time, although we may find it difficult to believe, when there are other things to talk about than Europe.

'At that point we will need all the talents arrayed within the party and not just those of Brexiteers.'

During the referendum campaign, Miss Rudd, a leading Remainer, attacked Mr Johnson as 'not the man you want driving you home at the end of the evening'. But she was also preparing to endorse him in the subsequent leadership contest until his campaign imploded.

The pair often lunch together and are friendly but, by supporting him, Ms Rudd would risk alienating allies who dislike his hardline Brexit views.

Some MPs think she is 'stringing him along' and will back a candidate more closely aligned with her own view of Brexit.

Tom Tughendhat, a rising star on the backbenches and chairman of the Foreign Affairs Committee, has told The Times rules out standing despite rumours he would be a contender.