We’d like to speak to him in connection with a serious assault on board a Tube train at Hornchurch yesterday (3 July).
At approximately 6.50pm, two men were seen to pursue a 21-year-old man through a District Line train and assault him.
One of the men punched the victim in the face which caused him to stumble and knock his head on a pole. He was then repeatedly kicked.
The victim was taken to hospital to be treated for a fractured jaw.
A 20-year-old man from Dagenham has been arrested and is currently in police custody.
Officers believe the man shown in this CCTV image may have information which could help the investigation.
Anyone with information should contact BTP by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 545 of 3 July. Alternatively, ring Crimestoppers anonymously on 0800 555 111.