The prime minister is "weighing up his options" ahead of a cabinet meeting on Tuesday morning after members of his government told him he should set a timetable for his departure.
Home Secretary Shabana Mahmood is among those telling Sir Keir Starmer he should announce a timeline, Sky's political editor Beth Rigby reports.
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"Some cabinet members… (are) telling him that the game is up," according to Rigby.
But other cabinet ministers – Housing Secretary Steve Reed and Work and Pensions Secretary Pat McFadden – have said the prime minister should fight on, she said. Both are key allies of Sir Keir.
Foreign Secretary Yvette Cooper and Defence Secretary John Healey went into Number 10 to speak to the PM on Monday night, Rigby understands. It's understood Ms Cooper did not join Ms Mahmood in calling for him to set a timetable for his departure.
Rigby added that Deputy Prime Minister David Lammy and Parliamentary Secretary to the Treasury Jonathan Reynolds have been by the PM's side, weighing up the options about what he should do.
It comes after four junior members of the government quit on Monday – with the tally of Labour MPs calling for Sir Keir's resignation now at 73.
'PM on the edge': Starmer dominates Tuesday's papers
The calls for his departure come after last week's election disaster for Labour, where the party lost almost 1,500 English council seats and Reform made massive gains for the second year running.
In Wales, Plaid Cymru held off Reform to become the largest party in the Senedd for the first time. The SNP lost votes in Scotland but remain the largest party. Both parties will need to work with others to hold a majority, however.
On Monday, Joe Morris, a parliamentary private secretary (PPS) to Health Secretary Wes Streeting, and Tom Rutland, a PPS to Environment Secretary Emma Reynolds, urged the prime minister to set out a timetable for his departure as they quit.
Cabinet Office aide Naushabah Khan and Melanie Ward, a PPS to Mr Lammy, also called for new leadership as they announced their resignations.
Downing Street replaced the four as part of a sweep of six ministerial aide appointments on Monday night.
Starmer speech fails to convince doubters
In a speech on Monday morning, Sir Keir promised to prove his "doubters" wrong and would not "walk away", but it failed to quell demands he quit or set out a timetable for his exit from No 10.
Scores of MPs have signed a letter from former Foreign Office minister Catherine West urging Sir Keir to do just that.
Ms West had previously said she would challenge Sir Keir for the party leadership as early as Monday afternoon, in a bid to force the cabinet to come up with a replacement as prime minister.
But she has now said she would canvass support within Labour for Sir Keir to set out a timetable for his resignation by September.
In his news conference, the prime minister announced measures including legislation to nationalise British Steel, a ban on "far-right agitators" coming to the UK for a planned march on Saturday and a plan to put the country "at the heart of Europe".
He said there was a "battle for the soul" of the UK, warning that if Labour failed, the nation would head down "a very dark path".
Afterwards, some backbenchers expressed support for the PM, with Macclesfield MP Tim Roca and Gedling's Michael Payne saying Sir Keir had shown he understood "the scale of the challenge" facing the country.
However, others from across the party – not just his usual critics on the left – demanded his resignation.
Any rival who wanted to contest the leadership would need to be nominated by at least 20% of Labour MPs, meaning the current magic number to hit would be 80.
Is Burnham the answer?
Some have suggested Greater Manchester Mayor Andy Burnham as a replacement PM, saying he should be allowed to return to parliament.
But Sir Keir would not be drawn on whether he would support Mr Burnham's return to Westminster, saying it was a matter for Labour's national executive committee (NEC).
The committee, which is dominated by Sir Keir's backers, blocked Mr Burnham from contesting the Gorton and Denton by-election earlier this year, and the formerly safe Labour seat was won by the Green Party.
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Former deputy prime minister Angela Rayner – who is also viewed as a potential leadership contender – told the Communication Workers Union that the decision to block Mr Burnham should be "put right".
Conservative leader Kemi Badenoch dismissed Labour's "pretenders jostling for his job", saying: "They are busy arguing over who should drive the car, but the truth is they are all heading in the wrong direction. They have no vision for the future."
(c) Sky News 2026: PM 'weighs up options' ahead of crucial cabinet meeting this morning<
Who is 'King of the North' and would-be prime minister Andy Burnham?
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