The top civil servant in the Home Office has resigned and said he intends to sue the government for constructive dismissal.
Sir Philip Rutnam said there had been an orchestrated campaign against him.
It comes after reports of tensions between him and Home Secretary Priti Patel, including allegations she mistreated officials – which she has denied.
BBC political editor Laura Kuenssberg said such a move was “highly unusual”.
Sir Philip said he believed his experience was “extreme” but part of a “wider pattern” in government.