UK Home Office chief civil servant Sir Philip Rutnam resigns and plans to sue the government for constructive dismissal, BBC reported.
According to the broadcaster, Mr Rutnam said he was stepping down amid what he described as an orchestrated campaign against him in government.
Earlier this week, the home secretary and Mr Rutnam issued a joint statement to say they were "deeply concerned" by "false allegations" made about Ms Patel.
The statement came as a response to reports suggesting that Sir Philip had been briefing the media against the home secretary, allegedly saying that she mistreated officials. Ms Patel denied all the claims.