Sir Mark Lyall Grant, the national security adviser, irritated Theresa May by talking over her

Men of Whitehall beware: Downing Street has let it be known that Theresa May does not take kindly to mansplaining.

No 10 is understood to have taken umbrage at male politicians, officials, diplomats and even journalists who talk over, patronise or fail to listen to the prime minister or her team.

Word has spread around Whitehall after an alleged incident involving one of Britain’s senior security officials. In hushed tones, officials repeat how Sir Mark Lyall Grant, the national security adviser, visited Downing Street where he “got into a lot of trouble” for mansplaining to the prime minister.

Officials were later told that Mrs May was fed up with the manner deployed by Sir Mark, an old Etonian whose previous job was UK ambassador to