Andy Burnham has startled British politics by the scale of his win in the Makerfield by-election.
He stormed to victory, beating Reform UK’s candidate Robert Kenyon by a majority of 9,231, nearly 4,000 more than Labour achieved at the 2024 general election.
The outgoing Mayor of Greater Manchester gained 54.8% of the votes cast, outperforming opinion polls.
Mr Kenyon trailed in second place with 34.5% of the vote.
Within hours of Mr Burnham’s decisive victory, former Transport Secretary Louise Haigh who was sacked by Sir Keir Starmer, was urging him to step aside to avoid Labour being plunged into a deeper civil war.
"I hope that he will consider an orderly and managed transition,” she said.
“We have said that the party is in an existential crisis and things cannot continue, and it was quite clear after the local elections, unfortunately, that he considered that business as usual would suffice.
"Andy has potentially shown what a changed Labour Party could bring."
As Mr Burnham appears to be heading to No10, one of the questions being asked is how quickly could he become Prime Minister?
Theoretically, he could be walking through the black No10 door within days but this depends on a number of factors falling into place.
The first is that Sir Keir agrees to step aside and so far he has shown no sign of doing so, having repeatedly vowed to fight any leadership contest.
So the idea of a PM Burnham within a week would be killed off by defiance from Sir Keir.
However, politics is all about momentum and numbers.
“King of the North” Mr Burnham will arrive back at the Commons with huge momentum given the scale of his victory and Parliament, which is a Royal palace, is in many ways still like a Royal court.
Most Labour MPs will now see Mr Burnham as the Prime Minister-in-waiting offering hope to their party and country, and will want to be in his camp, some with eyes on a ministerial job.
So calculations of level of support for Sir Keir, ex-Health Secretary Wes Streeting and other potential candidates made before the by-election are now largely invalid.
Labour MPs who have been loyal to Sir Keir, including Southport’s Patrick Hurley, were on Friday morning already shifting their backing to Mr Burnham.
Culture Secretary Lisa Nandy hailed Mr Burnham as the “only Labour politician who could have pulled off that result”.
To challenge Sir Keir, Mr Burnham or another contender would need the backing of 81 MPs, as well as support from local parties or unions.
But if there is significant shift from within the Cabinet and Labour MPs towards Mr Burnham, there may be a “coronation” rather than a contest.
Mr Burnham would still need to formally gain the required support including from MPs which he would do so easily.
Labour’s ruling National Executive Committee would set a timetable for a contest but with only one candidate it could be completed within days, according to Labour experts, without a vote of the membership.
So Britain could theoretically have a new Prime Minister before a ball is hit at the Wimbledon Championship which starts on June 29.
Such a swift departure for Sir Keir would be brutal and Mr Burnham could agree a more gradual timetable, over weeks, but he could be in place as leader for Labour’s conference in Liverpool at the end of September.
Mr Streeting, who launched stinging criticism of Sir Keir’s government when he quit as Health Secretary, has already been laying out his vision for Britain ahead of an expected Labour leadership contest.
The Ilford North MP, who is on the Right of the Labour Party, is unlikely to gain anywhere near Mr Burnham’s level of support.
So a contest, which could take place over the summer months, is not guaranteed.
But some MPs believe a “coronation” would be wrong and that there should be a contest so the new party leader and Prime Minister has a mandate, at least from MPs and party members, even if not from voters across the UK.
When MPs return to the Commons on Monday, it will be gripped with feverish speculation about whether Mr Burnham will be PM within days, weeks, months or not at all.
After his victory in Makerfield, the keys to No10 appear to be within his reach but how quickly he can gain them will depend significantly on the momentum of the political shift now happening within Labour.
