The top civil servant in the Home Office has resigned and said he intends to claim for constructive dismissal by the government.
Sir Philip Rutnam said there had been a “vicious and orchestrated” campaign against him in Home Secretary Priti Patel’s office.
Reported tensions between the pair included claims she mistreated officials – which she has denied.
The prime minister has “full confidence in his cabinet”, Downing Street said.
Sir Philip said he received allegations that Ms Patel’s conduct towards employees included “swearing, belittling people, making unreasonable and repeated demands”.
He said that behaviour had “created fear and needed some bravery to call out”.
It was his duty to “protect the health, safety and wellbeing” of 35,000 Home Office workers, he said, but that doing so had “created tension” between him and Ms Patel.
Sir Philip, who has had a career spanning 33 years, added he had attempted a “reconciliation” with Ms Patel but that she had “made no effort to engage with me to discuss this”.
He said he believed his experience was “extreme” but part of a “wider pattern” in government.
Sir Mark Sedwill, cabinet secretary and head of the civil service, thanked Sir Philip for his “long and dedicated career of public service” and said Shona Dunn, who had been Mr Rutnam’s deputy, will become acting permanent secretary.
He said he received the resignation “with great regret”, adding: “The Home Office’s vital work to keep our citizens safe and our country secure continues uninterrupted.”
It comes days after the home secretary and Sir Philip released a joint statement saying they were “deeply concerned” by various “false allegations” made about Ms Patel.
Allegations the pair dismissed included reports that Ms Patel, who has been home secretary since Boris Johnson became prime minister, bullied her staff and was not trusted by MI5 bosses.
While speaking with the BBC, Sir Philip said: “In the last 10 days, I have been the target of a vicious and orchestrated briefing campaign.”
He said allegations that he had briefed the media against the home secretary were among many “completely false” claims against him.
Sir Philip said he did not believe Ms Patel’s denial of any involvement in the false claims, adding that she had not “made the efforts I would expect to dissociate herself from the comments”.
Sir Philip said he intended to issue a claim against the Home Office for constructive dismissal.
He added that the Cabinet Office had offered him a financial settlement “that would have avoided this outcome” – but he turned it down.
For a claim of constructive dismissal to be successful at an employment tribunal, an individual must prove their employer seriously breached their contract and that they resigned in response to the breach.
Reasons for claiming constructive dismissal can include employers allowing bullying or harassment at work, or failing to support an employee in their job, according to Citizens Advice.