Keir Starmer is facing mounting pressure from all angles after a string of scandals, sackings and scathing attacks from inside his own party.
On Saturday night, fresh revelations in the story of Lord Mandelson's appointment and dismissal as British ambassador to the US came to light.
The peer was appointed to the post before a formal vetting process had taken place, Downing Street confirmed.
At the same time, it was reported that Labour rebels want suspended MP Andrew Gwynne to step down from his Greater Manchester seat so Mayor Andy Burnham can take over.
He would have to win a by-election against Nigel Farage's surging Reform UK before challenging Sir Keir for his job as party leader - and PM.
In the third blow from the Sunday papers, multiple "furious" ministers told The Times of their anger at the Lord Mandelson scandal, No10 chief of staff Morgan McSweeney, and an apparent lack of leadership in Government.
Labour rebels are said to want suspended MP Andrew Gwynne to step down from his Greater Manchester seat so Mayor Andy Burnham can run, then take over as Labour leader
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"I think it is pretty terminal, to be honest," one senior Government minister told the newspaper.
"Hushed conversations that are being had among friends are swiftly coming to the overriding conclusion that Keir cannot lead us into the next General Election. The only question left is who we are replacing him with."
Another minister said Downing Street was rudderless, and blasted: "There is no content or agenda, there is no political leadership.
"The PM can't keep asking someone else to tell him how to lead."
One Whitehall source said of Mr McSweeney: "Keir has lost control of his advisers. Heads have to roll."
One Whitehall source said of Mr McSweeney: 'Keir has lost control of his advisers. Heads have to roll'
| PAMeanwhile, Scottish Secretary Douglas Alexander told the BBC that Labour MPs will be feeling "despondent" after disgraced Deputy PM Angela Rayner's exit just last week.
One such Labour MP, Clive Lewis, openly questioned Sir Keir's future on Friday as he warned the Prime Minister was not "up to the job".
Mr Lewis said there was a "very dangerous atmosphere" among his fellow MPs.
Another, Barry Gardiner, told GB News that MPs were losing patience with Sir Keir's "missteps".
There is also said to be "fear" within the party that Sir Keir is handing Nigel Farage the keys to No10.
At the local level, Labour has lost 24 councillors to by-elections since the devastating May 1 locals - which also saw Reform's Sarah Pochin plant the flag for Mr Farage's party in a traditional Labour heartland.
In the same time period, Reform UK has gained 31 councillors.
There is also said to be fear within the party that Sir Keir is handing Nigel Farage the keys to No10
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At the parliamentary level, Reform is polling at near record highs.
Latest data from Find Out Now on September 10 revealed that 34 per cent of Britons would vote for Reform UK, while 19 per cent would vote for Labour.
When passed through Electoral Calculus's MRP simulator, such numbers would return 445 Reform MPs to the Commons and gut the Cabinet, including the Home, Foreign and Defence Secretaries - as well as the Chancellor.
Kemi Badenoch - whom Reform would also oust at its current polling level - accused Sir Keir of "spending the week lying to the whole country" about Lord Mandelson and Jeffrey Epstein's relationship.
Downing Street sources disputed her claims and questioned how expressing confidence in the ambassador could amount to a lie.
Find Out Now's polling, repeated at a General Election, would see Parliament represented like this - with 445 Reform MPs
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Again on Saturday, Elon Musk, who has moved to the right of Reform to back Ben Habib's Advance UK, called for a "dissolution of Parliament" and a "change of Government" in Britain, speaking to crowds via video-link at Tommy Robinson's "Unite the Kingdom" rally.
"I really think that there’s got to be a change of Government in Britain. You can't - we don't have another four years, or whenever the next election is, it's too long," he said.
"Something's got to be done. There's got to be a dissolution of Parliament and a new vote held."
Last month, his social media platform X warned that the Online Safety Act poses a serious risk to free speech.
That was the same warning Nigel Farage issued to the US Congress just days ago.
In three days, Donald Trump and his entourage will arrive in Britain for an historic second State Visit - which is expected to see the signing of a landmark technology agreement.
There are now fears Lord Mandelson, who was integral in organising the visit, could move to take down the Prime Minister with him when he returns to the UK.
One long-time party figure told The Telegraph: "He's a fighter, not a quitter, and I wouldn't want to be on the end of Peter Mandelson as a fighter."
Speaking to The Sun, Mr Gwynne denied he was poised to step aside for Mr Burnham, with a source close to the Manchester Mayor denying he is plotting a coup.
GB News has approached No10 for comment.