A policeman has been arrested over allegations he punched a senior detective in the face.

The victim, Detective Chief Inspector Nigel Smith of Sussex Police's professional standards department, was at police headquarters in Lewes when the alleged incident happened on Thursday.

One insider said: "He suffered bruising but did not need hospital treatment. There was a dispute over a personal and professional difference of opinion."

The officer who allegedly delivered the blow was arrested at the scene. He was later released on bail pending further inquiries.

He has been suspended from duty while the investigation takes place.

The professional standards department investigates complaints and discipline issues concerning police officers.