Allies of Andy Burnham are increasingly confident of a coronation-style transfer of power after the number of MPs backing his planned leadership bid surged following his byelection victory.

Burnham and his team are understood to have spent the last few days enlisting the support of MPs and ministers, as he prepares to challenge Keir Starmer in the coming weeks.

It was reported on Friday that, after his triumph in the Makerfield byelection, where he comfortably saw off the threat of Reform UK, Burnham’s team were hoping for 200 nominations, about half of the parliamentary party.

However, one minister said that figure was now “in the dust”, while another added that it was “logical” that the number of backers would be closer to 300, which could complicate a challenge from Wes Streeting.

The former Greater Manchester mayor is hoping to have enough support to dislodge Starmer from Downing Street without the need for a lengthy leadership contest.

However, an uncontested takeover is not favoured by all MPs, some of whom want the new Makerfield MP to face the “scrutiny” of his ideas being “put through the ringer” in a leadership contest.

Streeting and Burnham are expected to speak this weekend but sources close to the former health secretary insisted he also had the numbers to challenge Starmer and remained determined to do so, although they added that Streeting would not trigger a contest this weekend in order to allow the prime minister to “reflect on his position”.

Labour party rules mean that potential leadership candidates must secure nominations from at least 20% of the parliamentary party in order to force a contest.

The party has 403 MPs, meaning potential challengers would need the support of 81 to stand. They would also require the backing of 5% of local branches, and at least three party affiliated groups, of which a minimum of two must be trade unions.

Members would then vote for their preferred candidate, if more than one MP meets the criteria to stand.

Starmer, as leader, does not have to meet these requirements and would be on the ballot automatically unless he chooses to stand down. The prime minister has said that he will fight any potential leadership contest, which could take months.

However, previously loyal cabinet ministers warned the PM on Friday that he faced the indignity of being forced out of office by a string of damaging resignations if he did not set out a timetable for his departure.

Burnham secured a 9,000 majority in Thursday’s Makerfield poll, little more than a month after the constituency largely backed Reform in the local elections. His team now believe he is Labour’s best hope of preventing Nigel Farage’s party winning the next general election.

Although Starmer led Labour to a landslide general election victory in 2024, he is deeply unpopular with the electorate after a series of policy U-turns.

“We passed every single ridiculous test that they set – to win the way Andy has won, we smashed through every single ceiling they set, I think there couldn’t be a clearer message,” one Burnham ally said.

“It’s not a personal thing, but we can’t afford not to do this, we’ve got to be be honest with ourselves about where we are and what we need to do to keep a Labour government going and [Starmer] can’t do that sadly.

“This is an existential crisis for us, and it’s proven that there’s another way you can do things that navigates us through that. And I just think it’s unwise and sad that Keir and his team want to, at this point, not acknowledge or accept that. They’ve got time obviously, so we’ll see what happens.”

Jess Phillips, who resigned as safeguarding minister last month and is close to Streeting, said that while Burnham had beaten Reform “absolutely soundly” he should still face the “rigour of at least some manner of contests”.

She told the BBC Radio 4’s Today programme: “Lots of people don’t know Andy Burnham, have never worked alongside him, and that’s not his fault, unless you’re a Greater Manchester MP … I look forward to Andy Burnham arriving [in parliament] on Monday and those who are prospective candidates setting out their stall.”

Another close ally of Streeting said the “priority” for MPs was ensuring that Starmer understood he could not continue as leader.

They said: “There [are] two ways forward. One is orderly and comradely and gives the space for a forward-looking policy debate which could be a proper battle of ideas and whoever wins will come out stronger for it.

“And the alternative is one that is entirely focused on who’s to blame for what’s gone wrong in the last two years and extremely bitter and angry. I don’t think anyone wins in that scenario. That is within Keir’s gift.

“If Keir steps down, that does allow for a contest that is fought in a pretty collegiate way, because it won’t be about what’s gone wrong, it doesn’t have to be.

“I think putting [Burnham’s] ideas and [Streeting’s] ideas through the ringer and the challenge of media scrutiny and scrutiny from members means we’re more likely to come out of it with a stronger programme and a leader whose programme is tested and can then be put into action.

“I think there is also a risk of chaos if you don’t go into government with that kind of definition that you get from a campaign.”