'The game is over': UK PM Starmer said to be preparing to resign as early as Sunday

British Prime Minister Keir Starmer is preparing to resign after a prolonged effort to hold on, according to his own allies, as a leading Labour leadership contender won a seat in parliament and further narrowed his standing within the party. Observers inside and outside British politics say Starmer could announce his voluntary resignation as early as Sunday.

A senior British government official told the Daily Telegraph on Friday (local time) that a beleaguered Starmer has come to realize "the game is over" and is now preoccupied with how to "cement his legacy."

The official said there had been "significant movement" among cabinet ministers after Andy Burnham, the Mayor of Greater Manchester and a leading Labour leadership contender, won a parliamentary by-election on Wednesday. That shift, the official said, prompted Starmer to reconsider his previous stance of staying on.

Under Labour rules, only sitting members of parliament can stand for the party leadership. A leadership primary can be triggered if 20 percent of Labour lawmakers back the call — currently 81 of the party's 403 MPs.

In his victory speech after winning the by-election, Burnham signaled his intention to run for the leadership, telling the Labour Party: "This is the last chance to bring about change." He is reported to have the backing of nearly 300 lawmakers.

Starmer is weighing his options in part because voices within his own inner circle have begun calling on him to step aside for Burnham.

One lawmaker considered a Starmer loyalist said the prime minister's support base has now shrunk to a handful of "friends and family," and predicted he would announce a resignation timetable as early as Sunday.

"There is no one left. Literally, it is almost exclusively relatives who work in Downing Street or long-standing personal friends of the prime minister," the lawmaker said, adding that any attempt to block Burnham's path to Downing Street would be "like trying to defy gravity."

A government official also predicted "something will happen before the end of this week," warning that if Starmer does not step down voluntarily, "a mass collective resignation within the government could become a reality."

Since last month, several junior ministers have resigned while calling on Starmer to quit. More recently, Health Secretary Wes Streeting — seen as a potential rival to Starmer — and Defense Secretary John Healey left the cabinet after criticizing him. Foreign Secretary Yvette Cooper, Home Secretary Shabana Mahmood, Energy Security Secretary Ed Miliband and Transport Secretary Heidi Alexander are also reported to have urged Starmer to resign.

Another government source said Starmer spent the weekend weighing his future, adding that even those who had not previously called for his resignation were now telling him "it's time."

If Burnham calls for a leadership primary without Starmer first resigning voluntarily, the prime minister would automatically become a candidate.

However, one government source told the BBC that it would be "madness" to think Starmer could beat Burnham in a leadership primary. An acquaintance of the prime minister told the Observer that Starmer "is facing reality — preventing 'chaos' is no longer possible simply by staying on, so there is only one option left," predicting his resignation.

US President Donald Trump also weighed in, writing on Truth Social on Sunday that "Starmer will be resigning as Prime Minister of the United Kingdom," and went on to say: "He has failed miserably on two very important issues — immigration and energy. Good luck to him."

Starmer is reported to have spent the weekend at a country retreat with his wife as he weighed his options.