A moped gang knocked a biker to the floor after attacking him with a fire extinguisher.
Shocking footage from the victim's helmet camera shows the moment he was surrounded on Roden Street in Ilford. The gang tried to steal his bike but escaped empty handed.
Officers believe the gang carried out seven attacks on April 17 and 18 in the Barking and Dagenham area.
Anyone with information can contact the investigation team on 07766 247747, or via 101, or by tweeting @MetCC