Michael Gove had earlier told Mr Johnson privately
Cabinet ministers are heading to 10 Downing Street to tell Boris Johnson to resign.
The PM has faced a grilling in the House of Commons since admitting he had known about allegations of inappropriate behaviour by disgraced MP Chris Pincher in 2019 before hiring him as deputy chief whip in February 2022.
The scandal saw Sajid Javid and Rishi Sunak resign.
More than 50 ministers and aides have since quit.
Senior politicians, including the new Chancellor Nadhim Zahawi, headed into Number 10 to urge the PM to resign.
Transport Secretary Grant Shapps and Welsh Secretary Simon Hart also joined Chief Whip Chris Heaton-Harris to tell the PM his position is untenable.
Business Secretary Kwasi Kwarteng has also called on Boris Johnson to resign and has said so to the chief whip.
Michael Gove had earlier told Mr Johnson privately that it was time to go.
It is believed that Priti Patel is inside Number 10 while Culture Secretary Nadine Dorries has been backing Boris Johnson, saying the PM “consistently gets all the big decisions right”.
It was reported that Priti Patel was among those who told the PM to quit.
Newly appointed Chancellor Nadhim Zahawi publicly called for Mr Johnson to resign.
Prime Minister: this is not sustainable and it will only get worse: for you, for the Conservative Party and most importantly of all the country. You must do the right thing and go now. pic.twitter.com/F2iKT1PhvC
— Nadhim Zahawi (@nadhimzahawi) July 7, 2022
The ministers spoke to Mr Johnson one by one as 21% of the Conservatives’ 358 MPs (75) are now opposed to the Prime Minister’s leadership.
Despite the slew of resignations, the Prime Minister insisted that he would stay in power as it was “responsible just to walk away”.
Mr Johnson remains defiant and will not resign. He claimed that doing so would cause chaos.
The PM has since sacked Levelling Up, Housing and Communities Secretary Michael Gove.
Meanwhile, the executive of the Tory backbench 1922 Committee has been meeting to discuss whether to change the rules to allow a fresh confidence vote in the prime minister to take place.
The influential group decided it would hold elections for a new executive on July 11, and they could decide on any rule change the very same night.
Sir Graham Brady, chairman of the 1922 Committee, is expected “to offer wise counsel” to the PM.
Ministers had been sent out to defend Mr Johnson and say he did not know about any “specific” allegations.
Mr Pincher resigned as Chief Whip after further allegations that he groped two men at a private club in London, and he was later suspended from the Conservative Party.
Former senior civil servant Lord McDonald revealed on that the PM had been told in person of the 2019 allegations, despite what Downing Street was telling the press.
Less than 12 hours later, Mr Javid and Mr Sunak quit, prompting a flurry of more junior ministers saying they could no longer support Mr Johnson.