POLICE are appealing for information over an assault in Derry which left a man with a head injury.
A 29-year-old man intervened to stop another man being assaulted on Whittaker Street at around 2am on Friday, December 4.
He was then punched in the face and fell, hitting his head on the ground.
The victim needed treatment in Altnagelvin Hospital.
The person who allegedly threw the punch then made off in the direction of the Diamond along Shipquay Street.
Police said the attacker was said to have been wearing a dark top and green trousers.
Anyone with information is asked to ring police at Strand Road on the non-emergency number of 101.