A slow-motion political drama is unfolding inside the Labour Party, with the prime minister, Sir Keir Starmer, facing the most serious challenge to his leadership since winning a landslide majority two years ago. For the first time, a potential successor has publicly declared he would run against him – and the prime minister has now told supporters he would fight any contest rather than step aside.
At the centre of the story is the Greater Manchester mayor, Andy Burnham. On Thursday 5 June, appearing on BBC Question Time, Burnham said he would seek to become Labour leader and prime minister if he wins a by-election on 18 June in the constituency of Makerfield. “I think Wes Streeting seems to have launched a leadership contest,” Burnham said, referring to the former health secretary, “so if that is running, I would seek to join it. But I’d have to persuade members of the Parliamentary Labour Party to do the same.” Streeting has confirmed he would stand in any contest and has encouraged voters to back Burnham in Makerfield because he wants a “proper contest with the best candidates on the field”.
“The Labour Party faces a potential leadership contest. Here's what you need to know about the process, the candidates, and what happens next.”
The Labour Party has a formal process for challenging a sitting leader, but it has not yet been triggered. Under party rules, a leadership challenge requires the support of 20% of Labour MPs – currently about 80 names – to force a vote. No such threshold has been reached. But the pressure on Starmer has been building since last month, when Labour suffered historically poor local election results, losing control of the Welsh Senedd and nearly 1,500 councillors in England. Several junior ministers and Streeting resigned from the government in the aftermath. Starmer has consistently said he would not walk away if a contest were held, but until now there was a question mark over whether he would actively fight it. According to the BBC, after Burnham’s public declaration, Starmer’s position “hardened” and he told supporters he would oppose any challenge. A No 10 spokesperson said: “The Labour Party has a process for challenging a leader and it has not been triggered. The Prime Minister will not walk away from the mandate he was given just two years ago to build a stronger, fairer Britain.”
For UK readers, this matters because it raises the possibility of a second change of prime minister within a few years – and because the outcome could reshape the government’s direction on everything from the economy to public services. If a leadership contest does happen, Labour Party members – not the general public – would choose the winner. Starmer, as the sitting leader, would automatically be on the ballot.
Q: What is a Labour leadership contest? A: It is a vote by Labour Party members to choose the leader of the party. It can be triggered by a challenge to the incumbent leader, requiring the support of 20% of Labour MPs. If triggered, all Labour MPs and MEPs can nominate candidates. The winner is then chosen by members in a postal ballot.
Q: Who are the main contenders? A: So far, two figures have said they would stand in any contest: Andy Burnham, the Mayor of Greater Manchester, and Wes Streeting, the former Health Secretary. Other names may emerge. Burnham is widely seen as the frontrunner. Sir Keir Starmer has said he will fight to remain leader.
Q: What is the Makerfield by-election and why is it important? A: The by-election on 18 June in the Wigan-area seat of Makerfield was triggered by the resignation of the previous Labour MP. Andy Burnham is standing as the Labour candidate. If he wins, he will return to the House of Commons, which is a requirement for anyone wanting to become party leader (under current rules, the leader must be an MP). The by-election is effectively a test of whether Burnham can build momentum for a leadership bid.
What happens next depends largely on the result of the Makerfield by-election. If Burnham wins, he will be in a stronger position to gather the MP nominations needed to force a contest. Even if he doesn’t, the underlying tensions in the Labour Party are unlikely to disappear. The prime minister still believes a leadership contest would “plunge the country into chaos”, but with his own position under sustained pressure, the next few weeks will determine whether the slow-motion coup accelerates or fizzles out.