The top civil servant at the UK's Home Office resigned on Saturday, threatening to send Boris Johnson's government into disarray.

Sir Philip Rutnam quit after ongoing reports of tension between him and Home Secretary Priti Patel.

In an explosive statement, Rutnam said he had received allegations of bullying about Patel and said he plans to sue the government for constructive dismissal.

The government has backed Patel, with Health Secretary Matt Hancock stating that he had always found Patel "courteous"

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Britain's top government official in the ministry responsible for policing and counter-terrorism resigned on Saturday, saying there had been an orchestrated campaign to remove him.

Philip Rutnam quit after reports of tensions between him and Home Secretary Priti Patel, including allegations she mistreated officials. Patel has denied the allegations against her.

Rutnam, who has worked the government for 33 years, took the unusual step of making a statement outside his home alleging Patel was behind the campaign to oust him.

"In the last ten days I have been the target of a vicious and orchestrated briefing campaign," he told reporters.

"It has been alleged that I have briefed the media against the Home Secretary. This along with many other claims is completely false," Rutnam said.

"The Home Secretary categorically denied any involvement in this campaign to the Cabinet Office. I regret, I do not believe her," he added

Rutnam said he had tried to reconcile with Patel, at the request of the cabinet secretary and Prime Minister Boris Johnson.

"But despite my efforts to engage with her, Priti Patel has made no efforts to engage with me to discuss this," he said.

Rutnam said that this gave him "very strong claims" for constructive dismissal, which he would be pursuing in the courts. He added while his experience was "extreme", it was part of a "wider pattern" in government.

He added that he had received allegations about Patel's behavior, including "shouting and swearing, belittling people, making unreasonable and repeated demands."

The Home Office directed calls for a request for comment to the Cabinet Office, responsible for the administrative functions of the government. The Cabinet Office did not immediately respond to a request for comment.

The government appeared to back Patel on Sunday. Health Secretary Matt Hancock told the BBC: "Priti is a very determined Home Secretary and she's probably closer to where the public are on the issues of law and order than any Home Secretary in recent history. I think she drives things forward.

"I also think she's extremely courteous. In every dealing I've ever had with her, she's been very courteous."

Patel was forced to resign as Britain's aid minister in 2017 over undisclosed meetings with Israeli officials.