Dominic Raab warned a “dangerous precedent” has been set in the report about bullying allegations as he resigned as Deputy Prime Minister and Justice Secretary.

In a letter to Rishi Sunak, Mr Raab said that too low a bar had been set for what amounted to bullying.

Mr Raab said that the report by the independent barrister Adam Tolley KC showed he never swore or shouted at anyone in his cabinet roles and had dismissed all but two of the claims.

The decision was announced 24 hours after Mr Raab and Mr Sunak received the report on Thursday morning. Allies of Mr Raab had said he had been fighting against pressure to quit.

Mr Raab said: “In setting the threshold for bullying so low, this inquiry has set a dangerous precedent. It will encourage spurious complaints against Ministers, and have a chilling effect on those driving change on behalf of your government - and ultimately the British people.”

It is unclear whether Mr Sunak discussed the report directly with Mr Raab before the decision. They had not talked by Thursday evening, a source familiar with events had said.

Three cabinet departures in six months

The departure means that Mr Sunak has lost three cabinet ministers in his first six months in the role. Boris Johnson is the only other prime minister to have seen that happen since 1979.

The Prime Minister was expected to make a decision on Friday or bring the issue to a head.

Mr Raab’s announcement means Mr Sunak must now fill a vacancy around the cabinet table.

Mr Raab tweeted a two-page letter at 9.48am on Friday. It was addressed to Mr Sunak and dated Friday 21st April.

Mr Raab wrote: “It has been a privilege to serve you as Deputy Prime Minister, Justice Secretary and Lord Chancellor. I am grateful to have had the opportunity to work as a Minister in a range of roles and departments since 2015, and pay tribute to the many outstanding civil servants with whom I have worked.

“Whilst I feel duty bound to accept the outcome of the inquiry, it dismissed all but two of the claims levelled against me. I also believe that its two adverse findings are flawed and set a dangerous precedent for the conduct of good government.

"First, Ministers must be able to exercise direct oversight with respect to senior officials over critical negotiations conducted on behalf of the British people, otherwise the democratic and constitutional principle of Ministerial responsibility will be lost."

'Never swore or shouted'

He added: "This was particularly true during my time as Foreign Secretary, in the context of the Brexit negotiations over Gibraltar, when a senior diplomat breached the mandate agreed by Cabinet.

“Second, Ministers must be able to give direct critical feedback on briefings and submissions to senior officials, in order to set the standards and drive the reform the public expect of us. Of course, this must be done within reasonable bounds.

"Mr Tolley concluded that I had not once, in four and a half years, sworn or shouted at anyone, let alone thrown anything or otherwise physically intimidated anyone, nor intentionally sought to belittle anyone.

"I am genuinely sorry for any unintended stress or offence that any officials felt, as a result of the pace, standards and challenge that I brought to the Ministry of Justice. That is, however, what the public expect of Ministers working on their behalf.”

There was no sign in the immediate aftermath of the letter of the report from Mr Tolley being published or any remarks from Mr Sunak himself.

Nor was there news about who will be the new justice secretary. It is unclear if the deputy prime minister title will be given to another Tory politician or dropped.

The other two cabinet ministers to have left Mr Sunak’s government were Sir Gavin Williamson and Nadhim Zahawi.

Sir Gavin quit as Cabinet Office minister, a role which saw him attend Cabinet, just two weeks after being appointed over claims of being heavy-handed with colleagues and fellow MPs - allegations he always denied.

Mr Zahawi was also sacked as Conservative Party chairman when it emerged he agreed to pay a penalty as part of a seven-figure tax settlement with HMRC.