Keir Starmer on the brink of resigning as Andy Burnham heads to Westminster

The Prime Minister, who has spent the weekend mulling his political future, is reported to have been told by members of his Cabinet, including Foreign Secretary Yvette Cooper, that he should set out a timetable for his departure.

No 10 said Sir Keir’s position remained unchanged from Friday, when he said he will not “walk away” from Downing Street and will stand in any potential contest.

But Cabinet minister Peter Kyle did not shut down questions of Sir Keir considering quitting as he spoke to broadcasters on Sunday.

The Business Secretary said the Prime Minister was taking time to “think through what the political realities are today compared to last week, the week before”.

He said “I don’t know the decisions that he will make on behalf of our country”, but that “whatever unfolds” in the coming days will be a “functional process”.

It is understood that Mr Burnham is looking for a transition of about a month, which would give Sir Keir time to get his Defence Investment Plan over the line in time for the upcoming Nato summit and sign his planned EU co-operation deal at the second annual reset summit with the bloc in July.

It is thought Mr Burnham’s camp would however accept a timetable that sees Sir Keir in No 10 until September.

Questions are being raised within Labour about how a change of leader would come about – with some backing a leadership contest and others a swift transfer of power to Mr Burnham.

York Central MP Rachael Maskell said she thought “a smooth transition and handover” over the next month would be best.

“I think it’s widely believed that even if there was a contest, that Andy Burnham would win that with a considerable majority, and therefore I do question why we need to go through that process,” she told the Press Association.

Labour peer Baroness Harriet Harman suggested the Parliamentary Labour Party could endorse Mr Burnham to give him some “legitimacy” if there are no other candidates.

Another Labour MP cast doubt on whether former health secretary Wes Streeting has the backing or would be a realistic competitor for Mr Burnham even if he does, telling PA “there is no point having a contest if there is no second candidate”.

Mr Streeting suggested last week he was willing to trigger a contest and had the backing to do so, but there has since been speculation he could instead make a deal for a role in Mr Burnham’s Cabinet.

The number of Labour MPs calling for Sir Keir to go has topped 100 – just under a quarter of the party’s cohort in the Commons – and includes some who signed a letter warning against a leadership contest just last month.

Labour grandees have also spoken out, with former home secretary Alan Johnson saying Sir Keir should step aside and Lord Falconer saying he has “no authority” because it is assumed he will be replaced by Mr Burnham.