Theresa May to make decision on whether to delay the meaningful vote on her Brexit deal.

The prime minister's closest allies don't know if the House of Commons vote will go ahead on Tuesday as planned, according to multiple reports.

The EU cancels a key meeting in the Brexit process amid speculation of the Westminster vote being delayed.

May could go back to Brussels and ask the EU to make concessions on the most controversial aspects of the Withdrawal Agreement, like the backstop for avoiding a hard Irish border.

However, EU sources say there is no appetite for renegotiation.

Senior Conservatives like Home Secretary Sajid Javid are preparing for a leadership contest to replace May.

LONDON — Theresa May is set to make a crucial decision on whether to delay the House of Commons vote on her Brexit deal as the prime minister faces a massive defeat which could endanger her job.

Downing Street will decide on Monday whether to go ahead with the so-called "meaningful vote" on Tuesday, according to multiple reports, with over 100 Conservative MPs and almost all Labour MPs set to vote against the deal.

There is widespread confusion among the prime minister's allies and foes about whether the vote will go ahead on Tuesday as planned, with senior government figures rating the chances 50/50.

It has also emerged that the European Union cancelled a meeting of its Article 50 General Affairs Council which was scheduled to take place on December 18. The meeting was supposed to be where the Withdrawal Agreement was handed over to the European Parliament for ratification for the next stage of the Brexit process.

The prime minister has up to now been adamant that the vote on her controversial deal will go ahead as planned despite a growing number of MPs publicly announcing their intention to vote against it.

However, as things stand, over 100 of May's own Tory MPs are set to vote against the Withdrawal Agreement while Labour is confident that all of its own MPs will do the same. The Democratic Unionist Party which props up the Conservative government, is also planning to vote down the deal.

The prime minister is considering going back to Brussels and asking for changes to the deal which could win around MPs back in Westminster. May had phone calls with European Commission President Donald Tusk and Irish Taoiseach Leo Varadkar on Sunday evening ahead of a defining week for both Brexit and her leadership.

However, there is little prospect that the EU will make the sort of concessions May needs to satisfy MPs before the vote.

"I can't see much appetite here unless her [May's] red lines are changed. No deal planning will be stepped up," a senior source in Brussels told Business Insider on Monday morning.

A number of pro-Brexit MPs have said they will not support the deal unless the backstop for avoiding a hard border on the island of Ireland is changed to give the UK the right to leave the arrangement unilaterally.

The EU has said that it will not make major concessions on the backstop, meaning a slight a change of wording to the Political Declaration on the future UK-EU relationship might be the best May can realistically hope for.

Heavyweight Conservatives prepare for leadership contest

Meanwhile, senior Conservatives are stepping up preparations for a Tory leadership contest amid the widespread belief that the prime minister could be gone within weeks or even days.

Home Secretary Sajid Javid has reportedly been asking Tory MPs to support his leadership bid. "Sajid is tapping us up. He is very direct," one Cabinet minister told The Sun. Another senior Conservative MP added: "[Javid] told me that Theresa’s Brexit deal is s***, she’ll be forced out when it falls, and he is then going to declare immediately."

Javid is set to host a drinks reception in Westminster this month with House of Commons Leader Andrea Leadsom. A friend of Leadsom told BI that a Javid-Leadsom leadership team would be a "dream ticket" for Conservative MPs, as Javid's pro-Brexit credentials would be boosted by having a lead Leave campaigner on his team.

Foreign Secretary Jeremy Hunt, his predecessor Boris Johnson, and ex-Brexit Secretary Dominic Raab are also all considering leadership bids, according to multiple reports over recent days.