Sir Keir Starmer is expected to set out a timetable for his departure from Downing Street as potential successor Andy Burnham returns to Westminster.
The Prime Minister’s position appears untenable following Greater Manchester mayor Mr Burnham’s decisive victory in the Makerfield by-election.
On Monday morning preparations appeared to be made in Downing Street for an announcement with sound equipment set up outside the famous black door of No 10.
Sir Keir spent the weekend mulling his political future with his wife Lady Victoria Starmer as support drifted away from him at Westminster.
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 ministers have done little to dispel the impression that Sir Keir will signal his intention to leave Downing Street.
Sir Keir will “make his own decisions” about whether to resign, a minister has said.
Education minister Baroness Jacqui Smith told Times Radio: “My understanding from those I’ve spoken to who are close to the Prime Minister yesterday is that the Prime Minister has spent the weekend thinking really carefully about the future of the country, about what’s the best thing to do for the British people.”
She added: “He always thinks carefully about the future of this country and the interests of the British people – he puts them, by the way, ahead of the interests of the party – and he will make his own decisions in the light of what obviously everybody can see is a considerable amount of pressure and turbulence.”
If Sir Keir resigns as Labour leader it would trigger a contest to replace him in which supporters of Mr Burnham hope the new Makerfield MP would be the only candidate.
But there is no guarantee Labour MPs would agree to a coronation, with other candidates able to stand if they can gather the 81 supporters, a fifth of the party’s strength in the Commons, necessary to enter a contest.
If Mr Burnham is not swiftly installed as Labour leader and prime minister, Sir Keir faces major international summits looking like a lame duck leader.
The Prime Minister is expected to attend a gathering of Nato leaders in July and the UK-EU summit with Brussels’ chiefs later that month.
US President Donald Trump has already said he expects Sir Keir to resign, saying he “failed badly” on tackling immigration and refusing to open up the North Sea for the oil and gas industry.
Mr Burnham is expected to take his seat in the Commons on Monday after being returned to Westminster following last week’s by-election, which saw him convincingly defeat the challenge from Nigel Farage’s Reform UK in the seat.
Labour MPs nervous about their own seats given the party’s national poll ratings have seized on his victory as evidence that he could potentially help them see off the threat from Reform.
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