Main developments

Sir Keir Starmer has laid down the gauntlet to his critics, insisting to his cabinet that he will fight on as prime minister and challenging rivals to launch a formal Labour leadership contest.

“The Labour Party has a process for challenging a leader and that has not been triggered,” he said. “The country expects us to get on with governing. That is what I am doing and what we must do as a cabinet.”

Starmer’s defiant position at Tuesday’s cabinet meeting came shortly after Miatta Fahnbulleh became the first minister to quit his embattled government. Later, safeguarding minister Jess Phillips, victims minister Alex Davies-Jones and health minister Zubir Ahmed also resigned.

The prime minister’s comments, released by Number 10, mean he is challenging his rivals to secure the backing of 81 Labour MPs, the threshold required to trigger a leadership race.

All eyes are now on Wes Streeting to see whether he launches a formal challenge, even though the health secretary has repeatedly insisted he will not instigate a contest.

Separately, Andy Burnham, Manchester mayor, has identified a Labour MP willing to resign from their seat to allow him to fight a by-election and return to Westminster, one person briefed on the situation said. This would in turn enable Burnham to potentially seek the Labour leadership.

With more than 90 Labour MPs calling on Starmer to quit or set out a timetable for his departure, according to the website LabourList, the prime minister’s authority was rapidly draining away.

At the cabinet meeting Starmer read out a statement indicating his intention to continue as prime minister, which no one in the room challenged, and then immediately moved discussion on to the Iran war, according to government insiders.

People briefed on the discussion said Starmer told ministers he would only discuss recent events with ministers individually, but then declined to speak to them after the meeting.

Loyalist ministers took the unconventional step of giving interviews after the meeting to say that the prime minister still had their full support.

Work and Pensions Secretary Pat McFadden confirmed to Sky News that no one around the cabinet table challenged Starmer. “He will carry on with his job, as he should, as the public would expect him to do,” he said.

The number of Labour MPs who have publicly backed Starmer — more than 100 — still remains higher than those who have called for him to quit.

UK government bonds fell on Tuesday as Starmer battled to salvage his premiership.

Thirty-year gilt yields rose as much as 0.14 percentage points to 5.81 per cent, their highest level since 1998, as the pressure mounted on the prime minister following disastrous local and devolved election results for Labour.

Investors said some demands from Labour’s “soft left” MPs had added to the market pressure, including demands from the Tribune Group for changes to the UK’s debt targets.

Starmer chaired the cabinet meeting knowing that some ministers, including home secretary Shabana Mahmood, wanted him to set out a timetable for his departure.

But Mahmood’s spokesperson said on Tuesday she was not planning to quit Starmer’s government.