Brexit-supporting Tory MPs are frantically urging their colleagues to join the revolt against the Prime Minister by sending a letter of no confidence to Graham Brady, chairman of the 1922 Committee.
A political crisis has engulfed Mrs May after she last week announced the draft withdrawal agreement for leaving the EU, prompting a wave of ministerial resignations, including Brexit secretary Dominic Raab.
A plot to remove Mrs May from Downing Street was mounted by pro-Brexit Tory MPs, including influential leader of the European Research Group (ERG), Jacob Rees-Mogg.
At least 42 Tory MPs have given “firm assurances” that they have submitted letters of no confidence in the PM, according to the Sun.
To trigger a no-confidence vote, at least 48 Tory MPs – 15% of the 315 in parliament – are required to send letters to Brady, who secretly keeps track of how many have been submitted.
Over the weekend senior Tory MPs Zac Goldsmith and Bill Cash joined the ranks of Tory rebels who want Mrs May to be replaced – taking the total public declarations to 25.</span>
ON THE BRINK: Tory MPs have almost reached the threshold to trigger a no-confidence vote (Pic: GETTY)
There are thought to be 17 more Tory MPs who have submitted letters to Brady, who would be responsible for overseeing the contest and setting a timetable for the campaign.
One Tory MPs described today as “judgement day” for Mrs May amid fears the rebellion may falter if the no-confidence letter threshold is not reached.
Steve Baker, a former Brexit minister and now central figure in the rebellion, has urged his colleagues to submit letters if theyre serious about toppling Mrs May.</span>
REBEL: Steve Baker is a key figure in the Brexit wing of the Conservative party (Pic: GETTY)
“The captain is driving the ship at the rocks”
Simon Clarke MP
He told The Sun: “If everyone does what theyve told me, the line will be crossed by a big margin on Monday evening.
“However, it has become very very clear that not everyone does what theyve said theyre going to do.
“Conservative Members of Parliament who have decided that the only way to change the policy is to change the leader must have the courage and integrity to write the letter themselves.
“Simply telling me theyre going to obviously isnt good enough.”
Simon Clarke, Tory MP for Middlesbrough South and East Cleveland, said today is a “crucial day” for the PM, telling his fellow lawmakers that “this must be the point at which action is taken”.</span></span>
STANDING FIRM: Theresa May has vowed to 'see it through' as she faces a rebellion (Pic: SKY NEWS)
"This is absolutely the day at which we stand at the bar of history on this," Clarke told the BBC.
"If we continue with this plan we are simply not going to have a government because the clear threat it poses to the integrity of the union is something which our colleagues the DUP will simply put up with," he said.
Clarke, who has submitted a letter of no confidence, said every hour and every day that the Brexit deal was not rejected, was a day wasted on credible negotiations.
"It is quite clear to me that the captain is driving the ship at the rocks," he said
Rees-Mogg confirmed he was among the Tory MPs who have submitted a letter of no-confidence in Mrs Mays leadership.
In an audacious veiled threat in the House of Commons last week, hardline Brexiteer Rees-Mogg raised the spectre of sending a no-confidence letter if what the PM says and does “no longer match”.
Mrs May now faces the prospect of a no-confidence vote, which could see her ejected from No10 if more than half of all Tory MPs fail to back her.
The cabinet support she gained has now largely evaporated after a spate of resignations, including former cabinet ministers Raab and work and pensions secretary Esther McVey.
Junior ministers, among them Shailesh Vara, Suella Braverman and Anne-Marie Trevelyan, have also quit in protest of the deal, which they claim doesnt respect the result of the 2016 referendum.
Knives have been drawn by MPs across the spectrum, with Raab saying the deal amounted to “blackmail” and Labour leader Jeremy Corbyn describing it as a “botched deal”.
But addressing MPs in the Commons, the PM was defiant, issuing a rallying cry to MPs to get behind her Brexit deal “in the national interest”.
She conceded that negotiating Brexit has been a “frustrating process” but hailed her withdrawal agreement as a “decisive breakthrough” after two years of fraught talks.</span></span>
MICHAEL GOVE: Theresa May have found support in unlikely places (Pic: GETTY)
Mrs May will go on the attack over her Brexit plan on Monday, using a speech to say that the withdrawal agreement has been "agreed in full" as her own MPs press for late changes.
Less than a week before a European Council summit, where EU leaders are due to rubber stamp the Prime Minister's deal, she is braced for fresh attacks from inside and outside her own party.
Her speech is due to address those – thought to include up to five serving ministers – who think changes can be made to her deal before the November 25 summit.
She is expected to say that there is "an intense week of negotiations ahead of us", adding: "During that time I expect us to hammer out the full and final details of the framework that will underpin our future relationship and I am confident that we can strike a deal at the council that I can take back to the House of Commons.
"The core elements of that deal are already in place. The Withdrawal Agreement has been agreed in full, subject of course to final agreement being reached on the future framework."</span></span>