Andy Burnham has moved a step closer to posing a leadership threat to Sir Keir Starmer, declining to rule out stepping down as Greater Manchester mayor early.
Leaving his post would pave the way for a return to the Commons, opening the door to a possible Labour leadership challenge.
He is one of the favourites among Labour MPs to succeed Sir Keir, whose dismal poll ratings have led to speculation that he could be ousted before the next general election, due by 2029.
Mr Burnham said yesterday that it was his “full intention” to remain in position in Manchester until 2028, when his mayoral term ends. But significantly, he added: “If events change, I’m not necessarily going to be stuck religiously in one way of thinking.”

Asked if he had ambitions for the Labour leadership, Mr Burnham, who served as health secretary in Gordon Brown’s government, told BBC Radio Manchester: “I have never ruled out going back to Westminster. And obviously, I do watch what is going on down there.”
Mr Burnham, who has made two failed leadership bids in the past and was badly beaten by Jeremy Corbyn in 2015, appeared to signal he would only make a fresh attempt if he had strong Labour support.
“This is the thing I want to get over to people – it wouldn’t be me saying, ‘Right, I’m going to put myself right out there again.’ It would have to come in a different direction.”
Challenged about reports that he could stand for a parliamentary seat in Greater Manchester, he said: “I honestly don’t know. It’s a hypothetical question.
“Before anyone leaps to ‘Who’s the next person?’ it’s got to be ‘Why have we had a decade now of real turbulence?’”
Sir Keir is facing growing questions over his leadership of the Labour Party and the country after a disastrous fortnight, which saw the resignation of his deputy, Angela Rayner, and the sacking of his ambassador in Washington, Peter Mandelson, amid questions over his links to Jeffrey Epstein.
And as the contest for the deputy leadership of the Labour Party gets underway, with former Commons leader Lucy Powell battling it out against Bridget Phillipson, some Labour MPs believe the only solution to the party’s woes would be a complete change of leadership.
A new campaigning group within the party, Mainstream, was launched by Mr Burnham last week and could become a vehicle for that new direction.
The group says it is the home for Labour’s “radical realists” and is “serious about winning a democratic socialist future”.
But in an interview earlier this week, Ms Powell dubbed fevered speculation around the possible return of Mr Burnham “kind of sexist”.
“You’ve got two strong women in an open and transparent contest.
“And instead of talking about the two strong women, everybody’s talking about this being a sort of proxy war between two men, which, quite honestly, I find kind of sexist,” she told the BBC.