Nadhim Zahawi, who was appointed Chancellor on Tuesday evening, has told Prime Minister Boris Johnson to “do the right thing and go now”.

In a letter on Treasury note paper, Mr Zahawi said he was heartbroken by the leader's failure to step down after more than 50 resignations from the government. “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," he said. "You must do the right thing and go now.”The avalanche of resignations from Boris Johnson's government continued unabated on Thursday, raising pressure on the prime minister to bow to his colleagues' demands to quit.

Education Secretary Michelle Donelan has resigned telling Mr Johnson she could see "no way" he could stay in the post. Hours earlier Brandon Lewis, the Northern Ireland secretary, became the fourth Cabinet member to step down, following Welsh Secretary Simon Hart who quit on Wednesday night, and Rishi Sunak and Sajid Javid who sparked the revolt on Tuesday.

More than 50 members of Mr Johnson's team have now quit.

Mr Johnson met ministers in No10 on Wednesday, where he was told that he has lost the confidence of the Conservative Party and should not continue in office ― but he refused to listen and instead insisted he would battle on.

Mr Johnson faces the prospect of another confidence vote, orchestrated by the Tory 1922 Committee of backbench MPs.

A new executive for the committee will be elected next Monday and could change the leadership rules, allowing for another confidence vote just a month after the last one ― which the Prime Minister may lose given the way MPs have deserted him since Tuesday.

Mr Lewis told the prime minister that he was submitting his resignation with “regret”, but said that a divided Conservative Party cannot win elections.

The Northern Ireland secretary, who took over the role in early 2020, told Mr Johnson that the government had taken “huge strides to level up the economy of Northern Ireland and have not shied away from taking other difficult decisions; confronting the practical issues with the Northern Ireland Protocol, advocating for the reproductive rights of women and championing the benefits of integrated education for all”.

Mr Lewis continued: “A decision to leave government is never taken lightly, particularly at such a critical time for Northern Ireland. I have taken a lot of time to consider this decision, having outlined my position to you at length last night."

Mr Lewis told the prime minister that in recent months, the Conservative Party has been “relentlessly on the defensive, consumed by introspection and in-fighting”.

“A divided party cannot win elections. It cannot deliver for those who trusted us with their votes for the first time in 2019.”

Other MPs to announce on Thursday that they had had enough were Helen Whateley, Damian Hinds, George Freeman, Chris Philp and James Cartlidge.

How did it come to this?

The latest scandal, which has pushed Mr Johnson to the brink, surrounds his handling of the Chris Pincher affair, an MP accused of groping men while drunk. Mr Pincher stood down last week from his position as a whip, a position intended to ensure the good behaviour of MPs. Downing Street has been accused of failing to give straight answers about what Mr Johnson knew about previous accusations against Mr Pincher.

On Wednesday night, Welsh Secretary Mr Hart resigned, swiftly followed by an announcement from Attorney General Suella Braverman that she would stand in a leadership contest and called on Mr Johnson to leave.

It capped a day of drama in which dozens of ministers and aides resigned, meaning Mr Johnson had suffered more resignations than any British prime minister in history.

Despite this ― and despite a delegation of his most senior ministers going to Downing Street to try to persuade Mr Johnson to throw in the towel ― the prime minister remained defiant and was determined to press on.

He began a new reshuffle, sacking the levelling up secretary Michael Gove.

Mr Gove, who, like Mr Johnson is a former newspaper columnist, teamed up with the prime minister to campaign for Brexit in the referendum.

He was sacked by Theresa May when she took power after the shock result but returned to the front line in the Johnson team in 2019.

Mr Gove was appointed education secretary in 2010 when the coalition took over from Labour.

The BBC reported a Downing Street source who said the sacking of Mr Gove was a purge of those who were disloyal.

“You cannot have a snake who is not with you on any of the big arguments who then gleefully briefs the press that he has called for the leader to go," the official was quoted as saying.

“You cannot operate like that.”

Throughout the day, Mr Johnson gave a spirited defence of his position on the floor of parliament on Wednesday after losing dozens more colleagues, including Mr Javid and chancellor Mr Sunak.

In a particularly brutal swipe, Mr Javid accused Mr Johnson of sending ministers out to publicly lie for him.

“I also believe a team is as good as its team captain and a captain is as good as his or her team,” he told the House of Commons.

“It’s not fair on ministerial colleagues to go out every morning defending lines that don’t stand up and don’t hold up.”

Mr Javid suggested he had been disturbed by what was going in Number 10 in recent months.

“Effective governance inevitably requires loyalty and collective responsibility, of course it does, and I am instinctively a team player and I have completely focused on governing effectively over the last year,” he said.

“But treading the tightrope between loyalty and integrity has become impossible in recent months.”