Newly appointed chancellor Nadhim Zahawi publicly called on Boris Johnson to resign, telling the prime minister: “You must do the right thing and go now.”
The dramatic intervention came just two days after Mr Zahawi was appointed to replace Rishi Sunak, who quit as chancellor on Tuesday.
A source close to Mr Zahawi made clear he is not resigning, however, adding: “The country needs a chancellor and he will serve as long as he’s asked to do so.”
Moments after the new chancellor’s call for Mr Johnson to resign, Michelle Donelan, who was promoted to education secretary two days ago, also quit her role.
Earlier on Thursday morning, Brandon Lewis, the Northern Ireland secretary, resigned, telling Mr Johnson in a scathing letter that government requires “honesty, integrity and mutual respect”.
Mr Zahawi’s call came following another day of high drama at Westminster, which saw the PM hit with an avalanche of ministerial resignations. But he dug in and refused to resign.
Later on Thursday, Mr Johnson finally decided to call it a day. He was due to announce his resignation imminently.
Despite vowing to “fight on” just last night, the prime minister spoke with the chairman of the Conservatives’ 1922 Committee and agreed to stand down.
It is expected he will remain in post until a new Tory leader is in place by the party’s annual conference in October, a No 10 source said.
A Downing Street spokesperson added: “The prime minister will make a statement to the country today”.
It came after two more cabinet ministers also left government. Michael Gove, the levelling up secretary, was sacked and branded a “snake” by No 10.
Simon Hart, the Welsh secretary, also resigned on Wednesday night.
He had been among a “delegation” of cabinet ministers who went to No 10 to tell him that he should listen to the overwhelming view of his party.
