Boris Johnson resigned as leader of Britain's governing Conservative Party on Thursday, but intends to continue as prime minister until the fall, when a new party leader is chosen.

The controversial move came after an unprecedentedly dramatic 36 hours of domestic politics, which began with Tuesday's announcement that Health Secretary Sajid Javid and Chancellor of the Exchequer Rishi Sunak would step down, triggering an avalanche of further resignations and declarations of no confidence in Johnson as leader.

The culmination of the mass outbreak of internal dissent came when Nadhim Zahawi, who was only appointed as chancellor on Tuesday evening, and who on Wednesday morning told Sky News that he backed Johnson and it was "easy to walk away from government… but much tougher to deliver", called on Johnson to go.

In addition, Education Secretary Michelle Donelan, who was also appointed on Tuesday evening, resigned on Thursday morning.

Shortly after 9 am, with more than 50 members of the government having quit, the news broke that Johnson, who became prime minister in July 2019, would step down－but only as party leader.

"It is clearly now the will of the parliamentary Conservative Party that there should be a new leader of that party and so a new prime minister," said Johnson in an address delivered outside 10 Downing Street. "I've agreed ... that the process of choosing that new leader should begin now."

He added that he will serve "until a new leader is in place".

Unhappiness with Johnson's leadership and personal conduct had been growing in the Conservative Party for months, culminating in his being fined by the police for breaking rules on social gatherings during the pandemic lockdown.