BRITISH Transport Police have released a CCTV image of a man they want to interview about a sex assault on a train.

The man got on the 7.31pm train from Darford to Charing Cross at Slade Green railway station and sat opposite an 18-year-old girl, even though there were many other empty seats.

He then approached her, touched her indecently and got off the train at the next stop in Erith.

Police say despite extensive enquiries since the incident on July 24, they have not been able to identify the man.

Anyone who recognises him should call the transport police on 0800 405040 quoting incident 542 of July 24 2010.