British Transport Police officers investigating what is described as a racially aggravated common assault at Elephant & Castle tube station have released a CCTV image of a man they wish to trace.
The incident happened at 7pm on Monday 18 July at Elephant & Castle Underground Station.
According to the police, a man made racial comments towards the victim as he was boarding a lift to ground level.
In the Northern line booking hall the man attacked the victim by punching him in the jaw.
PC Ben Pereira said: "I am keen to speak to anyone who was in the area at the time or anyone who may have witnessed the incident.
"This was an unprovoked attack which has left the man shaken.
"Everyone has the right to travel on the rail network without fear or intimidation."
Anyone with any information should contact British Transport Police on 0800 40 50 40 or text 61016 quoting reference 166 of 15/08/2016.