Theresa May is on her way home from Paris to face a showdown meeting with senior Tories in a secret location where her critics warned there would be 'blood on the walls'.
The Prime Minister will hold talks with members of the executive of the 1922 Committee of backbench Conservative MPs who will threaten to topple her within the next month if she won't 'do her duty' and quit.
Brexiteer MP Bob Blackman, who sits on the executive, said today: 'If she doesn't give us a clear timetable, it will be set for her'.
Nick Timothy, Mrs May's former chief of staff, said today that it is 'beyond time for the Prime Minister to accept the game is up', adding she 'risks killing the Conservatives for good'.
'Her premiership has failed - her authority is shot. Every day wasted from here makes life harder for whoever leads Britain into the future. We need to end this national humiliation', he said.
Mrs May will face the 18-strong 1922 at Westminster but members won't be told the location until an hour before it starts to avoid leaks.
Insiders are calling it one of the most important meeting since the Tory committee of backbenchers was formed in 1923 because the party is on the verge of civil war over Brexit.
Some Tories want her to stay - claiming it won't solve their Brexit conundrum - with one telling MailOnline: 'Changing the pilot doesn't change the weather'.
Theresa May, pictured in Paris with French President Emmanuel Macron last night, will face the 1922 committee of MPs at 11.30am today where she will be told to name the date she is leaving
The Prime Minister was in Paris last night for talks with Emmanuel Macron and EU leaders on how to eliminate violent and terrorist content from the internet.
Back home she is insisting she won't quit until a Brexit deal is passed - but talks with Labour have hit the buffers as they demand a customs union and ponder making a second referendum the price of any deal.
And more than 100 Tory MPs are predicted to vote against the EU Withdrawal Agreement Bill (WAB), which was defeated by 58 votes in March.
With the Brexit Party also expected to hammer the Conservatives in the European elections on May 23, there is a clamour for the PM to go to way for a new leader by the summer.
Mrs May's Brexit deal could be 'dead' in weeks, Cabinet ministers warned yesterday, as sources claimed that the June vote could be her final act as Prime Minister as grassroots members are planning a vote of no confidence.
1922 Committee treasurer Sir Geoffrey Clifton-Brown said today: 'It would be infinitely preferable if she set a date rather than us force her out.
'It's better that she does it than we have a vote of confidence. What I would like to see is her set out a timetable to trigger a leadership contest.'
After the talks with the Prime Minister, the 1922 Committee executive will hold a private meeting where changes to Tory leadership contest rules could be discussed, according to sources.
At present, Mrs May cannot be challenged again as leader until December.
Tory MP Andrew Bridgen: 'I would like to see the 22 give her a timetable to stand down. And, if she does not accept that timetable, tell her we will have another vote of confidence after the European elections.'
Prominent Brexiteer Mark Francois said that a predicted poor Tory showing in next week's European Parliament elections would heap pressure on Mrs May to go.
He said: 'As the polls increasingly suggest, we are going to have an extremely difficult night in the European elections.