Officers received a report of a phone stolen along Effingham Road just before midnight on Friday the 28th of March.
The victim was approached by three men on a moped, wearing balaclavas, one punched him, brandished a knife and robbed him.
The suspects were around 5ft 8’ to 5ft 9’, around 20-years-old, slim, in black balaclavas, jackets, tracksuit bottoms and black trainers.
Officers are urging any witnesses or anyone with dashcam or doorbell footage to contact them on 101.
