The Home Office's top civil servant, Sir Philip Rutnam, has resigned and said he intends to sue the government for constructive dismissal after what he called a "vicious and orchestrated" campaign against him.
Here is his statement in full:
"I have this morning resigned as permanent secretary of the Home Office.
I take this decision with great regret after a career of 33 years.
I am making this statement now because I will be issuing a claim against the Home Office for constructive dismissal.
In the last 10 days, I have been the target of a vicious and orchestrated briefing campaign.
It has been alleged that I have briefed the media against the home secretary.
This - along with many other claims - is completely false.
The home secretary categorically denied any involvement in this campaign to the Cabinet Office.
I regret I do not believe her.
She has not made the efforts I would expect to dissociate herself from the comments.
Even despite this campaign I was willing to effect a reconciliation with the home secretary, as requested by the cabinet secretary on behalf of the prime minister.
But despite my efforts to engage with her, Priti Patel has made no effort to engage with me to discuss this.
I believe that these events give me very strong grounds to claim constructive, unfair dismissal - and I will be pursuing that claim in the courts.
My experience has been extreme but I consider that there is evidence that it is part of a wider pattern of behaviour.
One of my duties as permanent secretary was to protect the health, safety and well-being of our 35,000 people.
This created tension with the home secretary, and I have encouraged her to change her behaviours.
I have received allegations that her conduct has included shouting and swearing, belittling people, making unreasonable and repeated demands - behaviour that created fear and that needed some bravery to call out.
I know that resigning in this way will have very serious implications for me personally. The Cabinet Office offered me a financial settlement that would have avoided this outcome.
I am aware that there will continue to be briefing against me now I have made this decision, but I am hopeful that at least it may not now be directed to my colleagues or the department.
This has been a very difficult decision but I hope that my stand may help in maintaining the quality of government in our country, which includes hundreds of thousands of civil servants loyally dedicated to delivering this government's agenda.
I will make no further comment at this stage."