The UK Prime Minister will chair a crucial meeting of her Cabinet this morning as her position looks increasingly uncertain.

At the beginning of a week that was supposed to end with the UKs withdrawal from the EU, the House of Commons is facing another week of heated debate on the best way forward for Brexit.

Less than 24 hours after announcing that she would bring the Brexit Withdrawal Agreement back to the House for another meaningful vote, it is now unclear whether she will be able to.

Mrs May spent Sunday afternoon locked in crisis talks with members of her party at her Chequers country estate.

Prominent Brexiteer former Cabinet members Boris Johnson, Jacob Rees-Mogg and David Davis were around the table, along with leading figures from the backbench European Research Group group - Jacob Rees-Mogg, Steve Baker and former Tory leader Iain Duncan Smith.

File photo shows UK PM Theresa May speaking during a cabinet meeting at Chequers, her official country residence, in July 2018 | Image: Joel Rouse/Crown Copyright/PA Archive/PA Images

After the meeting, Downing Street gave no indication as to whether she was able to gather “sufficient support” to bring the deal back to Parliament.

Reports this morning indicate that the message from the meeting was that if Mrs May wants Brexiteer support, she must set out a clear timeline for her departure, with another leader in place to negotiate the UKs future relationship with the EU.

She held the meeting as Sunday Newspapers in the UK reported that a Cabinet coup was already under way – and throughout the day, a growing number of MPs put pressure on her to set a date for her departure.

An effigy of UK Prime Minister Theresa May passing Trafalgar Square during the ‘Put it to the People’ march, 23-03-2019. Image: SOPA Images/SIPA USA/PA Images

Meanwhile, the People’s Vote campaign said more than one million people joined a march in London on Saturday calling for a second EU referendum.

The ‘Put it to the People’ march was hailed as "one of the biggest protests in British history."

After the Cabinet meeting this morning, Mrs May is due to deliver an update on last week’s EU summit to Parliament.

At the meeting in Brussels, European leaders agreed to delay Brexit until May 22^nd – offering Mrs five weeks less than she requested.

The extension is also dependent on the Withdrawal Agreement receiving Parliamentary approval.

British Prime Minister Theresa May, centre, speaks with Dutch Prime Minister Mark Rutte, right, and Lithuanian President Dalia Grybauskaite, left, during a round table meeting at the EU summit in Brussels, 21-03-2019. Image: AP Photo/Frank Augstein

After Mrs May’s update today, the House of Commons is due to vote on a series of amendments aimed at influencing the process.

One proposal will attempt to wrest control of Parliamentary business from the Government and, if that is successful, a series of indicative votes will be held aimed at finding a majority in favour of a specific course.