The Brexit Secretary, Dominic Raab, could lead a mass exodus after Brussels last night rejected a compromise on the Northern Ireland border he had tabled yesterday.
And in worse news for the Prime Minister, one of the Brexiteers organising attempts to remove her as party leader said the 48 letters needed from MPs to trigger a vote of no-confidence should be in place next week.
On a dramatic day, Mr Raab was sent to Brussels for unplanned talks with the EU chief negotiator Michel Barnier to resolve the future of the Northern Ireland border. At the same time, all 27 ambassadors of the other EU member states were called in by the European Commission for a surprise briefing leading to heavy speculation that a deal was close.
But the talks ended with no deal and senior Tory sources made it clear that time may be running out for Mrs May who had been hoping to unveil an agreement at the European council meeting of heads of governments on Thursday. She is due in Brussels on Wednesday.
The threat to Mrs May’s authority came as Mr Raab’s predecessor David Davis, who resigned over the Chequers proposal, called on pro-Brexit ministers in her 21-strong Cabinet to quit.
He said her latest Brexit plan was “completely unacceptable” and urged Cabinet ministers to “exert their collective authority”.
A source close to Mr Raab pointed out that his statement to Parliament last week specifically ruled out supporting the idea of the UK staying in the customs union under EU rule without an end date.
It is understood that this was the favoured option that Mrs May tried to get a select group in her Cabinet to agree.
Theresa May faces a threat from within her party over her Brexit intransigence
Along with Mr Raab another nine Cabinet ministers, including some Remainers, could quit
“It was politically quite useful for Dominic that he made that clear,” a source said.
Along with Mr Raab another nine Cabinet ministers, including some Remainers, could quit. These include International Development Secretary Penny Mordaunt, a potential leadership contender, Leader of the House Andrea Leadsom and Work and Pensions Secretary Esther McVey.
All have failed to publicly back Mrs May’s Chequers proposals in the last week. Also suggested as a possible quitter is International Trade Secretary Liam Fox.
Another name was a leading Remainer, Scottish Secretary David Mundell, who is concerned that a proposal which allows Northern Ireland separate status in the UK will stop him from fighting off Scottish independence.
It is understood that in a joint message Mr Mundell and Scottish Tory leader Ruth Davidson told the Prime Minister: “Having fought just four years ago to keep our country together, the integrity of our United Kingdom remains the single most important issue for us in these negotiations.”
Meanwhile a minister outside the Cabinet told the Daily Express – which crusaded tirelessly for the referendum in 2016 and a Brexit the people actually want – that “around a t hird” of ministers could quit.
The minister said: “A lot of us swallowed Chequers as a compromise but it would be hard to swallow much else.”
There were also suggestions Tory Leave supporters are manoeuvring to remove Mrs May.
One ex-minister said: “There’s a good chance we will hit 48 letters this week. Lots of constituents are writing to MPs urging them to put them in.”
Mr Barnier reportedly said later that the talks did not go well
MP Mark Francois, the vice-chairman of the European Research Group, said: “The Cabinet has by and large been kept out of the whole process.”
But he insisted: “We are not going to bring down the Government. We want to change the policy.”
He said Mrs May would not be able to get her Chequers proposals through Parliament with up to 80 Tory Brexiteers ready to vote it down along with the Northern Ireland Democratic Unionists.
The EU continues to play hard ball with a demand that Mrs May either agrees to a so-called Northern Ireland backstop which will keep Britain under Brussels rule in a customs union for a period with no time limit and no ability for the UK to leave unilaterally.
The alternative is to allow Northern Ireland to be hived off from the rest of the UK in a bid to solve the problem of the land border.
It is understood the meeting between Mr Raab and EU chief negotiator Michel Barnier was held so the Brexit Secretary could offer a compromise which would time-limit the backstop. But Mr Raab’s offer was rejected and hopes of a deal faded.
Mr Barnier reportedly said later that the talks did not go well.
A Downing Street source said: “There was no deal. Claims that we are just waiting for a political agreement is also nonsense. If there was a political agreement then Dominic Raab was there to make it. There are still significant problems, mostly around the Northern Ireland backstop issue.”
But Foreign Secretary Jeremy Hunt, a key ally of Mrs May, suggested progress could be made by Wednesday’s European Council meeting in Brussels.
Mr Hunt said: “There are still some big issues to settle. We are putting everything into trying to resolve these issues.”
In a joint statement from the Brexit department and Downing Street, a spokesman said: “In the last few days UK and EU negotiators have made real progress in a number of key areas. However there remain a number of unresolved issues relating to the backstop.”