Lawmakers in May's Conservative government want her to outline a timetable for her resignation in the case that the plan is not approved - an outcome that appears likely as of now.
The prime minister had previously said she would resign if her Brexit deal, which has been voted down three times this year, was accepted by British lawmakers.
Here is how the drama could play out over the next few months.
May's hands have been tied, knowing that to make concessions to Labour would lead to fury in her divided party.
He claimed Labour was now "95% of the way towards being a second referendum party".
In an effort to limit the fallout, the government has sent MPs off on a long half-term break immediately after the election.
A former Kent MP has defected from the Conservative group in Wales to join Nigel Farage's Brexit Party. The vote in early June will be the fourth time she has tried to get her exit agreement passed by parliament.
The talks, which have lasted almost two months, were convened in an attempt to agree on a Brexit plan that could stand a chance of being approved by Britain's fractured Parliament.
If the situation was not fraught enough, the PM must also contend with the arrival of Mr Trump for a long-awaited and controversial three-day State Visit.
Speaking after his selection, he said: "Brexit is a cause close to my heart, it's all about democracy".
Under the process, MPs will whittle what looks to be a crowded field of candidates down to two - with ordinary Conservative members voting to decide the victor.
Mr Johnson, who has confirmed that he would make a second bid for the post, would defeat Mr Raab in a run-off by 59 points to 41, and beat every other contender by an even bigger margin, according to YouGov. If the cross-party talks fail, move on to the next stage.
"Six wasted weeks while uncertainty paralyses our economy".
Known overseas for his gaffes and accused of misleading voters over Brexit, he is nonetheless loved by many ordinary members of the ruling Conservative party, who will have a say in their new leader.
May, in turn, pointed the finger at Labour's own divisions over Brexit.
Nigel Farage's new Brexit Party is enjoying a surge in support from voters who are frustrated at the governments failure to complete the divorce.
The victor of the leadership contest will automatically become prime minister and will take control of the Brexit process, which has plunged Britain into its worst political crisis since World War Two.
Britain was due to leave the European Union on March 29 but the bloc has extended the Brexit deadline until October 31 amid the political impasse in the UK. "Why would he help the Tory Party?"