Keir Starmer has said he will stand in a Labour leadership contest should one be triggered after Andy Burnham's decisive victory in the Makerfield by-election, adding he will not "walk away". This was reported by Qazaqyia.kz citing The Guardian.

He also warned that such a contest would "plunge us into chaos" and that Labour needed to "pull together" to contest the by-election to replace Burnham as the mayor of Greater Manchester.

The prime minister told reporters at an event in north London: "There isn't a leadership contest at the moment, there isn't one at the moment, but as I've said on many, many occasions, I don't think that's a good thing for the country, to plunge us into chaos.

"I would also add that now that Andy has won, which is really important, really good, he's a huge asset to us, that now there will inevitably be a Manchester mayoralty by-election starting straight away.

"It's important that we pull together for that, but if there is a contest, just to be clear with you, then, yes, I will run."

Burnham won the Makerfield by-election with 55% of the vote. In his victory speech, he said the result "could be a turning point" and that people had "voted for change, they have voted for more power for the north and everywhere forgotten by Westminster".

Some Burnham supporters had hoped the prime minister might decide against contesting a leadership race, with allies of the outgoing mayor saying he wanted to come to an agreement with Starmer next week about a timetable for a handover of power.

However, Starmer's indication that he will not allow a coronation for Burnham could set up a more protracted contest, with other candidates potentially coming forward as well. As the sitting Labour leader, Starmer will automatically be on the ballot if he decides to take part.

Speaking to reporters at the event, Starmer said: "If there is a contest, then, yes, I will stand. I have said repeatedly, I am not going to walk away from that."

In a challenge to Burnham's ambitions to replace him, Starmer stressed his "mandate two years ago" from the July 2024 general election in which he was elected with a landslide majority.

"In relation to what happens next, obviously, we had a mandate two years ago to carry out change and we've done incredible things.

"There's more to do and that's what I'm focused on. It is what I was elected to do, which is to serve my country."

Starmer's strategy is to put as many obstacles as possible in the way of Burnham, including the suggestion that the Greater Manchester mayoral election to replace him should take place first.

However, the scale of Burnham's victory against Reform heaps more pressure on the prime minister to consider standing aside. Starmer has already indicated he could offer his rival a top job, which Burnham has rebuffed. He said on Friday morning that he had not spoken to Burnham yet but that he would and had sent his congratulations.

Starmer framed the win in Makerfield as a sign Labour was making gains against Reform, rather than it being a personal victory for Burnham.

"I think it's further evidence, actually, if you look at it in the context of other by-elections, that the tide is turning on Reform, that they can't now win by-elections," he said.

"They've reached probably the peak of their support; it is going down. So, very good, congratulations to Andy Burnham, but actually the tide is turning on Reform as well, so this is really important in that respect."

One idea put forward by Harriet Harman, the former deputy leader of the party and now Starmer's adviser on women and girls, is for Labour MPs to oversee a contest rather than the decision being put to the whole party membership.

She suggested Labour MPs should be given a vote on "who they want as prime minister", telling BBC Radio 4's Today programme: "The way you get to be prime minister and the way you govern the country is by having the support of the majority of the party in parliament.

"So, whoever's prime minister has to have the support of Labour MPs, and I think what should happen is that the three contenders – which is obviously Keir Starmer, who's the prime minister; Andy Burnham, who's the challenger; and Wes Streeting, who's also a challenger – should be got in a room by the deputy leader of the Labour party, Lucy Powell, and the chair of the parliamentary Labour party, Jess Morden, to agree a process whereby the Labour MPs choose who they want."

She added: "There must be a woman in the contest" as "we cannot have a male beauty parade again".