Theresa May has promised Tory MPs she will stand down if they back her EU withdrawal deal.
She told backbench Tories: “I am prepared to leave this job earlier than I intended in order to do what is right for our country and our party.”
The PM said she knew that Tory MPs did not want her to lead the next phase of Brexit negotiations “and I won’t stand in the way of that”.
She did not name a departure date at a packed meeting of the 1922 committee.
But the BBC’s Laura Kuenssberg said a Tory leadership contest could be expected in May.
Downing Street said it would be a “different ball game” if the deal was not passed by Parliament.
It comes as MPs seize control of the Commons agenda to hold votes on alternatives to the deal.
Mrs May told the 300 or so Tory MPs at the meeting “we need to get the deal through and deliver Brexit”.
“I ask everyone in this room to back the deal so we can complete our historic duty – to deliver on the decision of the British people and leave the European Union with a smooth and orderly exit.”