Mr Sunak said “the public rightly expect government to be conducted properly, competently and seriously”, adding “I believe these standards are worth fighting for and that is why I am resigning.”
In an incendiary letter, 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”.
Mr Javid added that following last month’s vote of confidence “it is clear to me that this situation will not change under your leadership – and you have therefore lost my confidence too”.
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Mr Javid told the Prime Minister that the recent vote of confidence was a “moment for humility, grip and new direction”.
“I regret to say, however, that it is clear to me that this situation will not change under your leadership – and you have therefore lost my confidence too.”
He also told Boris Johnson: “You will forever be credited with seeing off the threat of Corbynism, and breaking the deadlock on Brexit.”
He continued: “The country needs a strong and principled Conservative Party, and the Party is bigger than any one individual. I served you loyally and as a friend, but we all serve the country first.
“When made to choose between those loyalties there can only be one answer.”
Mr Sunak suggested in his resignation letter to the Prime Minister that the Government is not being “conducted properly, competently and seriously”, as he told Boris Johnson that “our approaches are fundamentally too different”.
He wrote: “The public rightly expect government to be conducted properly, competently and seriously. I recognise this may be my last ministerial job, but I believe these standards are worth fighting for and that is why I am resigning”.
He also said he had been “loyal” to Mr Johnson.
“On those occasions where I disagreed with you privately, I have supported you publicly”.
Mr Sunak also wrote: “In preparation for our proposed joint speech on the economy next week, it has become clear to me that our approaches are fundamentally too different.
“I am sad to be leaving Government but I have reluctantly come to the conclusion that we cannot continue like this.”
Writing on Twitter, he added: “I recognise this may be my last ministerial job, but I believe these standards are worth fighting for and that is why I am resigning.”
The resignations came as Mr Johnson was forced into a humiliating apology over his handling of the Chris Pincher row 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 a private members’ club, but Mr Johnson was told about allegations against him as far back as 2019.
The Prime Minister acknowledged he should have sacked Mr Pincher when he was told about the claims against him 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.”