Andy Burnham confirms he plans to run to be an MP in upcoming by-election

Mr Burnham, who has long been considered a potential challenger to the Prime Minister for the Labour leadership, said the decision had been "difficult" but now was "the moment to mount the strongest possible defence of what we stand for".

His announcement was made just minutes before the 5pm deadline.

In his letter, he wrote: "Dear Chair, I write to seek the permission of the NEC to enter the process for the selection of Labour’s candidate for the forthcoming Gorton and Denton by-election.

"This has been a difficult decision for me to make and I thought it would help members of the NEC if I shared my reasoning in reaching it.

"Of course, nobody wanted or expected a by-election at this time and I have given careful thought to what is in the best interests of our Party and the city-region I represent.

"With that in mind, I have come to the conclusion that this is the moment to mount the strongest possible defence of what we stand for and what we have built in this city over many generations.

"Manchester inspires because it is a place that has always stood for the equality of all people, right back to the cotton workers of 1862 who refused to handle slave-picked cotton.

"In my time as Mayor, I have drawn strength from that tradition and worked hard to unite people. We are famous for our togetherness and, from that foundation, we are achieving huge success as the UK’s fastest-growing city region.

"And yet, there is now a direct threat to everything Greater Manchester has always been about from a brand of politics which seeks to pit people against each other.

"It brings with it a poison we should not let enter our city-region. I see this by-election as the frontline of that fight for the Manchester Way and I feel I owe it to a city which has given me so much to lead it from the front, despite the risks involved.

"With your permission to stand, I would run a hopeful and unifying campaign with broad appeal to voters, focusing on the positivity around what we have achieved, whilst at the same time being honest about the alienation people feel from politics.

"I left Westminster almost 10 years ago because I felt it too and had a strong sense that it wasn’t working for people in our part of the world.In my current job, I have tried to pioneer a different way of doing things with some success.

"But I have learnt in my nine years as Mayor that Manchester won’t be able to be everything it should be without similar changes at a national level. This is why I feel the need to go back.

"When so many people in a city-region like this are struggling to afford the daily basics, they are surely right to question why the country gave away control of them in the first place, in whose interests it is run and why no government of any colour has corrected these things for them.I applaud this Government for being the first in a long time to face up to them and put people before profit.

"The progress already made on rail renationalisation, bus re-regulation, the housing crisis and devolution is truly impressive.

"My role in returning would be to use my experience to help it to go further and faster, as well as communicate the difference it is making.

"I would be there to support the work of the Government, not undermine it, and I have passed on this assurance to the Prime Minister.

"I can assure the NEC that, if allowed to stand and successful in the by-election, I would give my all to the subsequent Greater Manchester Mayoral by-election.

"We have such a powerful story to tell of the change Greater Manchester Labour has brought to the city-region and I am confident we can win and take that success story into a new era.I hope this makes my reasoning clear and I attach the required form with further information.

"Out of respect for this internal process, I will not be giving any further public statements until it is concluded beyond the release of this letter.

"I am sad at the circumstances in which all this has come about and, while he clearly made mistakes, I want to recognise the dedicated service of Andrew Gwynne to this area over many years."

Despite his intention to run, Mr Burnham's bid could still be blocked by the NEC by refusing him permission.

Supporters of the Prime Minister are reported to be mobilising to prevent him from becoming a candidate.

Cabinet minister Ed Miliband welcomed Mr Burnham’s candidacy as he gave a speech to the Fabian Society’s annual conference in London.

Mr Miliband said Mr Burnham had done "an outstanding job" as mayor and would be "a massive asset" in Parliament.

He added he hoped the Gorton and Denton party would have "the option" of selecting him as a candidate, saying: "My view about this is Keir needs the best possible team serving under him in Parliament."

The by-election in Gorton and Denton was triggered by the sudden resignation of former Labour minister Andrew Gwynne, who was stripped of the Labour whip over offensive comments made in a WhatsApp group.

Although Mr Gwynne won the seat with 51 per cent of the vote in 2024, Mr Burnham could still face a tough fight given the collapse in Labour’s polling position and the rise of both Reform UK and the Green Party.

Green Party leader Zack Polanski, who was born in Salford, is reported to be mulling over standing in the seat.

If elected, Mr Burnham would be legally required to stand down as mayor of Greater Manchester, triggering a city-wide by-election.