Hours after the Prime Minister said her top team had agreed a draft Withdrawal Agreement, Brexit Secretary Dominic Raab resigned from the Cabinet and was soon followed out of the door by Esther McVey.
The resignations ignited backbench Tory Brexiteer anger which culminated in Jacob Rees-Mogg expressing no confidence in Mrs May, in a move expected to be matched other members of the European Research Group he chairs, hugely increasing the chance of leadership challenge.
The PM however remained defiant, insisting she would “see this through” and evoking the philosophy of her cricketing hero Geoffrey Boycott, pointing out that the Yorkshire batsman “stuck to it and he got the runs in the end”.
But amid a febrile atmosphere in Westminster, Mrs May failed to deny reports that Michael Gove making demands to renegotiate the deal if he is to accept an offer to step in as Brexit Secretary.
Rumours also continued to swirl around Westminster that more Ministers could quit, with Transport Secretary Chris Grayling and International Development Secretary Penny Mordaunt identified as ones to watch.
Mr Rees-Mogg submitted his letter of no confidence as Mrs May endured a hail of criticism during a three-hour Commons debate in which only a handful of Tories spoke in favour of an agreement thrashed out in 19 months of intensive negotiations.
Speaking to reporters outside Parliament, Mr Rees-Mogg said he believed the 48 letters needed to trigger a vote of no confidence would be submitted, but declined to say how soon.
If a challenge is triggered a majority to Tory MPs, 158, then have to vote to oust Mrs May
Mr Rees-Mogg also named Mr Raab, Ms McVey, Boris Johnson, David Davis and Ms Mordaunt as potential leadership candidates.
Opposition to Mrs May’s deal has focused on her failure to secure a unilateral escape route from the so-called backstop to maintain a soft Irish border.
But the PM said her opponents were ignoring two “inescapable facts” - that no one has put forward an alternative plan which fulfils the referendum result and maintains a soft Irish border, or which the EU would agree to.
She told a Number 10 press conference: “Leadership is about taking the right decisions, not the easy ones. As Prime Minister my job is to bring back a deal that delivers on the vote of theBritish people but also protects jobs and protects people’s livelihoods, protects our security, protects the Union of the United Kingdom.
“I believe this is a deal which does deliver that, which is in the national interest and am I going to see this through? Yes.”