A pizza delivery man was thrown from his motorcycle after a stunt by teenage pranksters in Lofting Road, Barnsbury on 26 February.
Youths tied a rope to a lamppost and stretched it across the road as the 28-year-old victim approached. He was struck in the chest and fell off his bike.
Witnesses saw a group of teenagers laughing and fleeing the area in the direction of Liverpool Road.
The victim was not seriously injured but the motorcycle was damaged.
Anyone with information about the incident is requested to contact Islington CID on 0207 421 0150.
