Keir Starmer expected to resign as UK prime minister on Monday after Burnham's by-election triumph

The pressure becomes overwhelming

The British prime minister's grip on power has loosened dramatically since Andy Burnham, the resigning mayor of Greater Manchester, stormed to victory in the Makerfield parliamentary by-election on Thursday. The result, seen as an eviction notice from Downing Street, triggered a cascade of interventions from senior Labour figures over the weekend.

Foreign Secretary Yvette Cooper privately urged Starmer to step aside, multiple outlets reported. Energy Security Secretary Ed Miliband, Home Secretary Shabana Mahmood and Transport Secretary Heidi Alexander were also said to have advised him to prepare a roadmap for his departure. Trade union leaders and party donors reinforced the message during a series of meetings over the past 48 hours.

Allies signal the end

Commerce Secretary Peter Kyle, until recently a vocal defender of the prime minister, told the BBC that Starmer was "reflecting on the new political realities" and twice declined to rule out a Monday announcement.

He is reflecting on the new political realities.

The Telegraph quoted a senior government figure saying Starmer now realises "the game is over" and is "focusing on how to consolidate his political legacy." One long-standing ally told The Sun there was now only a 25 per cent chance that Starmer would continue his fight.

Downing Street insisted on Sunday that the prime minister's position remained unchanged since Friday, when he declared he would stay in office and face any leadership challenge. But the Observer reported that Starmer had accepted the reality of evaporating parliamentary support, with a majority of Labour MPs now backing Burnham.

The Burnham challenge

Burnham, who will be sworn in as the MP for Makerfield on Monday, has secured the backing of more than 201 Labour parliamentarians, well over half the party's Commons contingent. His supporters say he is ready to launch a formal leadership challenge should Starmer refuse to resign spontaneously.

The mayor's return to Westminster after his thumping by-election victory against Reform UK has been framed as a direct threat to the prime minister's authority. A peer close to Starmer told the Observer that the PM now believes staying on would only prolong "chaos" and wants an "orderly, slow march" out of office as "a matter of duty and dignity."

What comes next

If Starmer announces his resignation on Monday, he is expected to outline a calendar for an orderly transition of power within weeks, rather than days. The handover would install Burnham as both Labour leader and prime minister, making him Britain's seventh prime minister in a decade, a churn without precedent in modern UK history.

Burnham is expected to meet Starmer in the coming days, and Labour officials are already discussing the mechanics of a leadership election that could be a formality if no other candidate emerges. The party remains deeply unsettled, with some reports also linking Starmer's unpopularity to the Epstein affair, though the prime minister's camp has not addressed that directly.