The twin Cabinet resignations came as the PM struggled to contain the fallout from the Chris Pincher row.
A humiliating apology from the Prime Minister was unable to prevent the departure of two senior ministers and potential leadership rivals, with both writing incendiary resignation letters.
Mr Sunak said “the public rightly expect government to be conducted properly, competently and seriously”, adicionando: “I believe these standards are worth fighting for and that is why I am resigning.”
Nadhim Zahawi was promoted to be the new Chancellor, with universities minister Michelle Donelan taking his place as Education Secretary.
Mr Javid said the British people “expect integrity from their government” but voters now believed Mr Johnson’s administration was neither competent nor “acting in the national interest”.
He was replaced as Health Secretary by Steve Barclay, the Prime Minister’s chief of staff.
The Prime Minister’s authority had already been damaged by a confidence vote which saw 41% of his own MPs withdraw their support.
The loss of crunch by-elections in Tiverton and Honiton and Wakefield in June triggered the resignation of party chairman Oliver Dowden, while there is still lingering anger over coronavirus lockdown-busting parties in Downing Street.
The twin resignations of Mr Javid and Mr Sunak mean Mr Johnson’s position is now perilous, but Cabinet ministers including Dominic Raab, Liz Truss, Michael Gove, Therese Coffey and Ben Wallace indicated they would be staying in the Government.
Contudo, Bim Afolami quit as Tory vice-chair live on TV, Theo Clarke and Andrew Murrison resigned as trade envoys and ministerial aides Jonathan Gullis, Saqib Bhatti, Nicola Richards and Virginia Crosbie left their roles.
The Prime Minister’s fate may ultimately lie with backbench MPs if the Tory 1922 Committee’s rules are changed to allow another confidence vote within 12 meses.
Allies of Mr Johnson believe that is unlikely as it would leave any future leader with a “gun to their head”.
A sign that the Prime Minister was in danger came with a hastily-arranged broadcast interview in his Commons office.
He tried to contain the row over Mr Pincher after it emerged he had forgotten about being told of previous allegations of “inappropriate” conduct.
Mr Pincher quit as deputy chief whip last week following claims that he groped two men at the upmarket Carlton Club, but Mr Johnson knew about allegations against him as far back as 2019.
The Prime Minister acknowledged he should have sacked Mr Pincher when he was found to have behaved inappropriately when he was a Foreign Office minister in 2019, but instead Mr Johnson went on to appoint him to other government roles.
Asked if that was an error, Mr Johnson said: “I think it was a mistake and I apologise for it. In hindsight it was the wrong thing to do.
“I apologise to everybody who has been badly affected by it. I want to make absolutely clear that there’s no place in this Government for anybody who is predatory or who abuses their position of power.”
MPs were told that Mr Johnson had not recalled being told about the earlier 2019 alegações.
Deputy Prime Minister Dominic Raab, the then foreign secretary, gave Mr Pincher a dressing down over his “inappropriate” conduct “in no uncertain terms” at the time and the Cabinet Office’s propriety and ethics team was also involved.
Não 10 had initially claimed Mr Johnson had not been aware of any “specific allegations”, after Mr Pincher’s dramatic resignation.
By Monday that line had evolved to acknowledge the Prime Minister was aware of “allegations that were either resolved or did not progress to a formal complaint”.
Cabinet Office Minister Michael Ellis told MPs “last week, when fresh allegations arose, the Prime Minister did not immediately recall the conversation in late 2019 about this incident”.
“As soon as he was reminded, the No 10 press office corrected their public lines.”
Mr Johnson denied lying to his aides about the situation.
The admission that Mr Johnson forgot about the earlier complaint came after the former top civil servant at the Foreign Office, Lord McDonald, said the original No 10 account was “not true” and the Prime Minister had been briefed “in person”.
As well as the Foreign Office complaint, Mr Johnson was also informed about another allegation against Mr Pincher at the time of the reshuffle when he was made deputy chief whip in February 2022, although this claim was “not taken forward”, according to No 10.
A third incident, the one which triggered Mr Pincher’s resignation, is now being examined by Parliament’s Independent Complaints and Grievance Scheme (ICGS).
Labour leader Sir Keir Starmer called for a general election, dizendo: “Only a real change of government can give Britain the fresh start it needs.”
In the Commons, the atmosphere among Tory MPs was mutinous with critics lining up to condemn the handling of the situation by Mr Johnson’s No 10 operation.
But ministers loyal to Mr Johnson rallied round him following the Tuesday night resignations.
Culture Secretary Nadine Dorries said he “consistently gets all the big decisions right”, while Brexit Opportunities Minister Jacob Rees-Mogg said the mandate won at the 2019 general election “should not be taken away from him because a number of people resign”.