Sir Keir Starmer has said he will not stand down as Prime Minister and intends to fight any contest for the Labour leadership, in a challenge to Andy Burnham after his win in the Makerfield by-election. 

Speaking on Friday morning, Starmer congratulated the former Manchester mayor after he won an emphatic victory over Reform UK but insisted he “will stand” in any contest.

“I’m not going to walk away from that,” he told broadcasters, referring to the mandate he won in 2024.

He suggested that the by-election was a “real battle of Labour values against divisive Reform values”. 

“The tide is turning on Reform,” he added. “They can’t now win by-elections, they’ve probably reached the peak of their support, it’s going down.”

Burnham’s win has left Starmer’s leadership under peril as scores of Labour backbenchers travelled to Greater Manchester to support the popular figure on his electoral campaign over recent weeks. 

Burnham has publicly said he would enter a leadership contest though it now remains to be seen how a race may be triggered. Speaking after his election victory, Burnham warned that Labour was facing its “last chance” to win any election. 

Challengers to Starmer must get the backing of at least 81 MPs in order to trigger a contest, with leadership hopefuls then having to gain support from unions and most members in order to win. 

Burnham suggested that Wes Streeting’s resignation from the government represented an opening for the job of Prime Minister. 

Streeting has said he has the necessary backing of 81 MPs needed to trigger a contest, though polls suggest that the former health secretary would be unlikely to beat either Burnham or Starmer in a contest. 

It has been reported that both Shabana Mahmood and Ed Miliband have privately urged Starmer to resign, though both remain in the Cabinet. Their resignations could add to tensions within the government, adding to last week’s blow when John Healey resigned as defence secretary.

“There is a chance now from this result tonight to build a new politics based on unity and hope. Turning away from the path that takes us to a divided, dark politics of the kind we see in the United States,” Burnham said.

“We must now take this path and put this country back on the right path, and bring people back together and get things working properly again.