Priti Patel has told Boris Johnson he has lost the support of Conservative MPs during crisis talks at Downing Street.
Speaking to Mr Johnson in Downing Street on Wednesday evening, the home secretary conveyed the overwhelming view of the parliamentary Tory party that his time at No 10 was up.
Though she has long been loyal to the prime minister, Ms Patel joined several cabinet colleagues who gathered in Downing Street to tell Mr Johnson he could not go on.
Other ministers present included Grant Shapps, the transport secretary, Chris Heaton Harris, the chief whip and Simon Hart, the Welsh secretary.
The Independent understands ministers went to meet the prime minister one-by-one to make their views known, with the home secretary telling him he had lost the support of his MPs.
Mr Shapps is thought to have told Mr Johnson that he stood little chance of winning another confidence vote and should instead set out a timetable for a departure on his own terms.
Business secretary Kwasi Kwarteng is also understood to have told Mr Johnson he should go.
Mr Johnson appointed Ms Patel home secretary on his first day in power and she has remained in post ever since. The pair have maintained an image of unity and have avoided public spats.
The prime minister sided with Ms Patel when a Cabinet Office inquiry found she had bullied staff, leading his ethics adviser to resign in protest when Mr Johnson rejected the findings of the investigation.
Even after losing the support of one of his most loyal ministers, Mr Johnson was understood to insist on remaining in office.
A senior ally of the prime minister told The Independent Mr Johnson refused to stand down when he spoke to members of his team. Before the Liaison Committee earlier the prime minister suggested he would be irresponsible to leave while the war in Ukraine raged.
But with his authority shot, the question of Mr Johnson’s departure will not go away and he could face another party vote on his leadership next week.
Under the current rules of the 1922 Committee of backbench Conservatives, the prime minister cannot face another challenge within a year of his shaky victory last month.
However, the rules could be torn up if the group’s executive accept a shorter waiting period when a new executive is elected on Monday.
Sir Graham Brady, chair of the committee, was believed to have visited Downing Street on Wednesday to communicate the views of backbenchers, following a meeting in parliament dominated by MPs calling for Mr Johnson to go.
Supporters of Mr Johnson also visited No 10 on Wednesday. Nadine Dorries, the culture secretary, said she and other cabinet ministers still supported the prime minister. Jacob Rees Mogg also pledged his support, as did Dominic Raab, the deputy prime minister, who defended Mr Johnson at the 1922 Committee meeting.
Mr Johnson’s leadership was left circling the drain after mass resignations in response to his handling of sexual misconduct claims against an MP he appointed deputy chief whip.
The fuse was lit by Sajid Javid and Rishi Sunak who resigned as health secretary and chancellor, respectively, within minutes of one another on Tuesday evening and were followed over the next day by at least 35 ministers, private secretaries and trade envoys.
