Theresa May faces having to accept a Brexit delay of up to a year that could split her party, after Europe said it had “little reason to believe” she had a plan she could get through parliament much sooner.

In a letter that inflamed Tory divisions, the President of the European Council Donald Tusk said a long delay would “allow the UK to rethink its Brexit strategy” and noted that revoking Article 50 in order to remain in the EU would be an option.

Such an extension is bound to increase calls from within the party for Mrs May to quit.

At a meeting of the Eurosceptic Bruges group addressed by Brexiter Tory MPs in Westminster yesterday, audience members repeatedly yelled “traitor” at the mention of her name.

Mrs May also suffered another huge Commons rebellion, with most of her MPs, including several ministers, breaking the whip to abstain or oppose even a short Brexit delay.

The Prime Minister has asked today’s emergency summit of EU leaders in Brussels to grant a Brexit delay until June 30 in order to avoid a chaotic no-deal exit on Friday. DUP leader Arlene Foster said it was painful to watch Mrs May “pleading” for more time, and said the PM had failed to show leadership or strength.

She said it was “humiliating that we are having to go and beg so that we can leave”, but said her party’s confidence and supply arrangement was with the Conservative party, not any particular leader, a reference to Mrs May’s looming departure from Downing Street.

To help her case, Mrs May meet German Chancellor Angela Merkel in Berlin and French President Emmanuel Macron in Paris on Tuesday, but to little avail.

With compromise talks between the Government and Labour stalling, and discipline among Tory ministers and MPs breaking down, EU leaders appear almost certain to reject the request because they see no evidence that Mrs May is about to break the impasse at Westminster.

Instead, the EU27 are expected to offer a flexible extension until the end of this year or until spring 2020 to give the UK time to put its house in order, with a break clause to allow Brexit to take place sooner if an agreement can be reached.

Any extension will require the unanimous consent of all 27 nations, and they are likely to set strict conditions, including “since cooperation” on the new EU budget and Commission, rather than obstruction by Mrs May’s successor.

READ MORE: MPs back Theresa May’s bid to extend Brexit process until June 30

At the Bruges Group meeting, Tory MP Mark Francois, vice chair of the European Research Group, said that the UK should cause maximum disruption.

He said: “If you attempt to hold us in the EU against the democratically expressed will of the British people then in return we will become a Trojan horse within the EU, which will utterly derail all your attempts to pursue a more federal project. If you now try to hold us in against our will you will be facing perfidious Albion on speed.”

EU leaders will also demand the UK participates in the European elections on May 23, warning that if it fails to do so, and has not ratified the withdrawal agreement, it will have to leave on June 1.

In a sign of Tory opposition to taking part, one of the party’s MEPs for East England last night refused to stand again as it would be “dishonourable”.

 In his letter to leaders, Mr Tusk said the EU27 would do their “utmost” to avoid a no-deal, which the International Monetary Fund warned yesterday would cause a two-year recession in the UK.

But he went on: “However, our experience so far, as well as the deep divisions within the House of Commons, give us little reason to believe that the ratification process can be completed by the end of June. In reality, granting such an extension would increase the risk of a rolling series of short extensions and emergency summits, creating new cliff-edge dates.

“This, in turn, would almost certainly overshadow the business of the EU27 in the months ahead. The continued uncertainty would also be bad for our businesses and citizens.”

He proposed an extension “of no longer than one year” based on a “number of conditions”, including not re-opening the Withdrawal Agreement, and UK passivity “in a manner that reflects its situation as a departing member state”.

Angela Merkel and <a href=Theresa May ">Angela Merkel and Theresa May embrace after their meeting at the chancellery in Berlin (Michael Sohn/AP)

He added: “In any event, the UK can revoke Article 50 at any time.”

He urged EU leaders not to let “negative emotions” cloud their decision.

“We should try the UK with the highest respect. Neither side should be allowed to feel humiliated at any stage on this difficult process,” he said.

A leaked draft of the conclusions of today’s summit left the extension date blank, but also insisted on the UK participating in the EU elections, and “acting in a constructive and responsible manner throughout this unique period”.

READ MORE: How would a second Brexit referendum work?​

It said the UK should help the EU achieve its tasks and “refrain from any measure which could jeopardise the attainment” of its objectives.

Both the draft text and Mr Tusk’s letter, which EU leaders can ignore and rewrite,  also said the EU would be willing to change the non-binding political declaration on future trade relations at short notice to help the UK arrive at a deal.

BrexitLabour MPs leave the Cabinet Office after Brexit talks with members of the Government (Yui Mok/PA)

However there was little progress in a fourth day of compromise talks between Tory ministers and Labour’s frontbench.

Number 10 said they had been “productive” and would resume tomorrow - showing the PM will not have a struck a deal before she addresses the EU27 tonight - but Labour said it had “yet to see the clear shift in the government’s position” that is needed to secure a compromise agreement”.

Tory divisions were also on show when MPs voted 420 to 110 in support of a government motion mandating the PM to seek an extension to June 30, a move forced on the government by the fast-tracked EU Withdrawal Act devised by Labour’s Yvette Cooper and Tory Oliver Letwin to avoid no-deal.

Only 131 of the 313 Tory MPs backed the government, with 97 voting against it, and 80 abstaining, including Commons leader Andrea Leadsom, International Trade Secretary Liam Fox, and Attorney General Geoffrey Cox.

POLITICS BrexitA breakdown of the result of the House of Commons vote authorising Theresa May’s request for extending Article 50 (PA Graphics)

Mr Fox also threw a spanner in the talks with Labour by describing Jeremy Corbyn’s plan for customs union as the “worst of both worlds”.

Writing to Sir Graham Brady, chair of the 1922 committee of Tory backbenchers, Mr Fox said a customs union would leave the UK unable to set its own global trade policy, while being forced to accept EU policies over which it no longer had any direct influence.

He said: “In such a scenario the UK would have a new role in the global trading system. We would ourselves be traded. As the famous saying in Brussels goes, if you are not at the table, you are on the menu.”

Mr Leadsom, the leader of the Commons, also flouted the government’s official line by saying it would be “fantastic” if the Withdrawal Deal could be reopened, despite the PM and EU repeatedly saying this was impossible.

READ MORE: What happens if the UK crashes out of the EU without a deal​

SNP Westminster leader Ian Blackford said: “The UK Parliament has proved incapable of making a decision so if there is an extension, the issue should be put back to the people. That means extending EU membership beyond June 30 to enable a referendum with Remain on the ballot paper to be held.”