Rebel Labour MPs are certain Sir Keir Starmer's reign is "coming to an end" as the Prime Minister pins his hopes on the state visit of Donald Trump.
Mr Starmer's allies are trying to fend off challenges to his leadership from Andy Burnham as Sir Keir comes under mounting pressure.
Revealed by The Telegraph, the Mayor of Greater Manchester has been laying the groundwork for a leadership bid, with a new campaign group calling on Downing Street to roll out wealth taxes, nationalise utility companies and end the two-child benefit cap.
Mr Burnham is expected to criticise the Prime Minister at Labour's annual party conference as he calls for a "reset" to help Labour win the next election.
In what has been inferred as a bid to secure an ally at the top of Labour, the Manchester Mayor has voiced his support for Lucy Powell in the party's deputy leadership race.
Senior Labour MP and former leader of Manchester City Council, Graham Stringer, said Sir Keir is "vulnerable" and "supping in the last-chance saloon" following the Lord Mandelson scandal.
Former frontbencher Richard Burgon said it was "inevitable" the Prime Minister "would be toppled if the 2026 local elections do not go Labour's well".
The former member of the shadow cabinet under Sir Keir's predecessor, Jeremy Corbyn, said: "Lots of MPs are looking to the elections next May, the opinion polls suggest it's going to be a complete disaster unfortunately.
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Sir Keir Starmer is under mounting pressure
| PA"I think it's inevitable that if May's elections go as people predict, and the opinion polls predict, then I think Starmer will be gone at that time."
He told BBC Radio 4's Today programme: "It feels like we are years and years into an unpopular Government, rather than a year into a Government that's just got rid of the Conservatives.
"We're losing votes to the left, we're going to be losing seats to the right."
Business Secretary Peter Kyle argued in favour of Mr Burnham remaining in Manchester.
Mr Kyle said: "Andy's a real talent. I think he's doing an incredible job in Manchester. I think Manchester really needs him.
"I like working with him in Manchester. It would be a shame for Manchester to lose him."
Mr Burnham would have to seek a seat through a by-election in order to stand as leader, with one option being the Manchester seat of Gorton and Denton where the MP Andrew Gwynne has been suspended since February after sending sexist messages on a WhatsApp chat.
Despite not currently being an MP, Mr Burnham previously served in Gordon Brown's Cabinet as Chief Secretary to the Treasury from 2007 to 2008, Culture Secretary from 2008 to 2009 and Health Secretary from 2009 to 2010.
Andy Burnham would have to seek a seat through a by-election in order to stand as leader
| PAThe new campaign from the Manchester Mayor has been compared to Together Labour, a British think tank, founded in June 2015 and closely associated with Keir Starmer's 2020 leadership election campaign, which opposed Jeremy Corbyn.
Political editor of Times Radio, Anna Mikhailova, told GB News: "There was already talk about Andy Burnham a week ago, before everything with Peter Mandelson.
"He also criticised Keir Starmer, not just the Government but the actual management style of the party, because a lot of this goes to the heart of how unhappy MPs are with how Number 10 and Starmer has been handling them from day one.
"Andy Burnham actually said, how can we have a Labour Party that has kicked out people like Rachel Musk.
"He actually namechecked the MP who was suspended over the winter over the welfare reform rebellion."