Sajid Javid has said "the problem starts at the top" and is "not going to change" in a stinging criticism of Boris Johnson after resigning as health secretary last night.

"Enough is enough," said Mr Javid, as he declared he was no longer willing to "risk losing my integrity" by serving in Mr Johnson's government.

"The reset button can only work so many times," he told a packed House of Commons.

"There's only so many times you can turn that machine on and off before you realise something is fundamentally wrong.

"The problem starts at the top, it's not going to change."

Mr Javid told the Commons he gave the Prime Minister the benefit of the doubt on partygate, but added “I do fear that the reset button can only work so many times”.

He said: “When the first stories of parties in Downing Street emerged late last year I was personally assured at the most senior level by my right honourable friend’s then team that, and I quote, ‘there had been no parties in Downing Street and no rules were broken’.

“So I gave the benefit of doubt. And I went on those media rounds to say that I’d had those assurances from the most senior level of the Prime Minister’s team.

“Then we had more stories. We had the Sue Gray report, a new Downing Street team. I continued to give the benefit of the doubt.”

After saying that “enough is enough”, Mr Javid said he appreciated the Prime Minister’s “kind and humble words, and his humble spirit when I went to see him yesterday”.

He added: “But I do fear that the reset button can only work so many times. There’s only so many times you can turn that machine on and off before you realise that something is fundamentally wrong.”

In an apparent message to members of the Cabinet who have stayed, Sajid Javid said “not doing something is an active decision”.

He told MPs: “Last month I gave the benefit of doubt one last time… I have concluded that the problem starts at the top and I believe that is not going to change and that means that it is for those of us in a position who have responsibility to make that change.

“I wish my Cabinet colleagues well and I can see they have decided to remain in the Cabinet. They will have their own reasons.”

Laughter could be heard in the chamber, as Mr Javid went on: “But it is a choice. I know just how difficult that choice is. But let’s be clear, not doing something is an active decision.”

He continued: “I am deeply concerned about how the next generation will see the Conservative Party on our current course. Our reputation after 12 years in government depends on regaining the public’s trust.”

He said if the Conservative ideals of “decency” and personal responsibility and the rule of law could not be upheld, “the Conservative mission to extend freedom and prosperity and opportunity is all at risk”.

Mr Javid triggered the wave of resignations on Tuesday evening, sending a letter to Mr Johnson saying he could "no longer, in good conscience, continue serving in this government".

"It is clear to me that this situation will not change under your leadership - and you have therefore lost my confidence too," he wrote.

After Michael Gove, Mr Javid was the most experienced member of the PM's cabinet, having served in David Cameron, Theresa May and Mr Johnson's front bench.

Under Mr Cameron, he was culture then business secretary, while Mrs May made him housing then home secretary.

The son of Pakistani migrants, he was the first person of colour to hold one of the "great offices of state" when Mrs May appointed him home secretary in 2018 following the Windrush scandal.

He ran for the Tory Party leadership in 2016 and again in 2019, when he came fourth and ultimately lost out to Mr Johnson.

Seen as a safe pair of hands, he was handed the most senior job beneath the PM - chancellor.

But in February 2020 Mr Javid quit after just 204 days over a falling out with Mr Johnson's former right-hand man Dominic Cummings, who asked him to sack all his political advisers to remain in the role.

He was the first British chancellor in 50 years not to deliver a budget.