Greater Manchester Mayor Andy Burnham has until 17:00 GMT on Saturday to decide if he wants to stand in the upcoming Gorton and Denton by-election.
Winning the parliamentary seat would enable Burnham to challenge Prime Minister Sir Keir Starmer for the party leadership.
However, there are several hurdles he must clear. First, as a directly-elected mayor, Burnham needs to get permission from Labour’s ruling National Executive Committee (NEC) to put his name forward as a candidate.
The BBC has been told that some of Sir Keir’s allies on the committee will seek to block him from standing – a move that could anger Labour MPs supportive of Burnham.
Burnham, a former Labour minister, has not confirmed whether he will apply to stand in the seat.
Asked on Thursday about the vacancy in the Greater Manchester constituency, he said he was “focused” on his job as mayor and cautioned people not to “rush to conclusions”.
Deputy Labour leader Lucy Powell, who sits on the NEC, appeared to indicate her support for Burnham telling an audience in London that she wanted “the very best candidate, the person who can most help Labour win in that by-election” selected.
She described Burnham as “an incredibly popular politician” and said he would have to “make up his own mind” about whether to stand.
Powell, who represents a Manchester constituency, said Labour members should “get behind Keir Starmer” adding that she didn’t want to see the by-election emerge into “in-fighting and talking about ourselves”.
There has been speculation that Sir Keir could face a leadership challenge after elections in May for the Welsh Parliament, Scottish Parliament and many local councils in England, which are expected to be difficult for Labour.
Nearly 30 councils have opted to delay elections this year due to a major reorganisation of local government.
Opposition MPs have criticised the delay, saying it would potentially disenfranchise millions of voters.
In order to enter any leadership race, Burnham – who has run twice before to be Labour leader – would have to be an MP.
He is expected to receive support from former deputy prime minister Angela Rayner, who the BBC understands will tell a Labour north west regional conference that the NEC should not block Burnham’s application.
Although Rayner resigned from government last year she still has strong support among some backbench MPs and members.
Several Labour sources have said they believe the NEC will block Burnham’s application to stand on the grounds that it would trigger an election for a new Manchester mayor, which would be expensive both for the party and the taxpayer.
The last mayoral election cost the Greater Manchester Combined Authority around £4.7m.
The NEC could also insist that there should be an all-women shortlist of possible Labour candidates for a by-election because the majority of the party’s MPs are currently men.
The decision will not be made by the full committee but the 10 NEC officers which include Sir Keir, Home Secretary Shabana Mahmood, deputy party leader Powell and party chair Ellie Reeves. There are also representatives from the GMB and USDAW trade unions.
The committee will tell Burnham what decision they have reached on Sunday.
The final deadline for all applicants to apply to be Labour’s candidate comes at midnight at the end of Sunday.
The area of Gorton and Denton has long been a safe Labour seat, and was won at the last election with 18,000 votes. Reform UK came second with 5,000 votes, narrowly beating the Green Party into third place.
Labour MPs are divided on whether they want Burnham to return to the House of Commons as an MP.
In a post on X, Labour MP and former shadow chancellor John McDonnell said blocking Burnham would “cause immense damage both to Keir and therefore the party”.
Cat Smith, MP for Lancaster and Wyre, said: “I think it would be disappointing if No 10 were to block strong candidates from being able to be considered by the party members in Gorton and Denton.”
Graham Stringer, the MP for Blackley and Middleton South, said “As a sitting Manchester MP, I don’t want to leave the back door open to Reform to have a go at getting the mayoralty of Greater Manchester.
“I think it’s very high-risk. By-elections are a nightmare for any candidates standing on behalf of a sitting government. I don’t think Andy should take that risk.”
