Andy Burnham has been cleared to run for selection in the Makerfield by-election following days of speculation that he will challenge Sir Keir Starmer's leadership.
Labour's National Executive Committee (NEC) agreed to allow the mayor of Greater Manchester to contest the seat.
A Labour Party spokesperson said: "Labour's ruling body, the National Executive Committee has today given permission to Andy Burnham to stand in the candidate selection process in the forthcoming by-election for the Makerfield constituency."
Mr Burnham, who dodged questions when he was spotted jogging by Sky News on Friday, has already confirmed his intention to stand in the by-election after the current MP, Josh Simons, announced he would quit parliament to make way for Mr Burnham.
Mr Burnham said he has wanted to "bring the change we have brought to Greater Manchester to the whole of the UK and make politics work properly for people".
Starmer latest: Andy Burnham clears hurdle in by-election bid
Mr Burnham previously wanted to stand as the Labour candidate in the Gorton and Denton by-election but his bid was blocked by the NEC.
Applications for the candidate selection process close on Monday and the NEC will endorse a candidate on Thursday.
It is thought that the earliest date the by-election near Greater Manchester could take place is 18 June.
If he is successfully elected, Mr Burnham is widely expected to challenge Sir Keir for the party leadership.
Labour expects a stiff challenge from Reform UK in Makerfield, with Mr Simons securing a majority of just 5,399 over Nigel Farage's party at the 2024 general election.
Since then, Labour's polling collapse and Reform's surge have seen their positions reverse.
This month's May elections saw Reform win every council ward in the Makerfield constituency, securing around half the vote, while Labour won only a little more than a quarter.
Read more:
Are all roads leading Labour to Andy Burnham?
Beth Rigby: Is the leadership race on?
Allies of Wes Streeting have told Sky News' Ali Fortescue that he will stand in any future Labour leadership contest.
It followed his resignation as health secretary on Thursday, when he delivered an explosive letter to Sir Keir accusing his government of "drift" and the PM himself of leaving a leadership "vacuum".
However, he did not trigger an immediate leadership contest himself as expected, calling instead for a "broad" debate about the party's future.
He also said he backed Mr Burnham to be the candidate in the upcoming by-election.
In a post on X, the now-former health secretary wrote: "We need our best players on the pitch. There is no doubt that Andy Burnham is one of them.
"The Makerfield by-election will be tough. Votes will need to be earned. Andy is the best chance of winning and that should override factional advantage or propping up one person."
? Listen to This Is Why on your podcast app ?
Housing Secretary Steve Reed, a close ally of Sir Keir, has admitted the PM is "unpopular".
He told Sky News: "It's not a good week that we just had, let me put that on the table straight away.
"It reminds me of what went on under the Conservatives, and I think we need to draw that to a close as quickly as possible."
Asked if changing an unpopular leader was necessary to beat Reform UK at the next election, Reed replied: "The prime minister is unpopular, but each of the last four prime ministers, in turn, has been the most unpopular prime minister we've ever had."
(c) Sky News 2026: Andy Burnham gets green light to run for selection in Makerfield by-election
Harvey Weinstein's rape retrial ends in mistrial after jury fails to reach verdict
New Ebola outbreak in Congo kills 65
Who is Look Mum No Computer - the electro 'Frankenstein' hoping to end UK's Eurovision drought?
Failed asylum seeker who left fake dynamite outside MI5 headquarters jailed
Man charged after Motherwell v Celtic referee’s personal details leaked
US influencer charged with assault over Tube station incident
Five Italians die while exploring underwater caves in the Maldives
Nazi-obsessed teenager who tried to behead Kurdish barber with an axe is jailed for more than 15 years