CCTV images have been released of a man police want to speak to in connection with a robbery on a Nunhead train.
Officers say they want to identify the man (pictured) as he may have information that could help their investigation.
The robbery happened on a train travelling from Elephant and Castle toward Nunhead at around 2.45pm on September 11 last year.
The victim, a man in his thirties, said he was approached by a man as the train pulled into Nunhead station.
He was then hit around the head and his phone was snatched by the assailant, who then ran off the train.
The victim followed him, shouting for help, but was pushed over by a second man on the stairs – where he hit his head.
British Transport Police are asking anyone with information to get in touch by texting 61016 or calling 0800 40 50 40.