British Transport Police detectives have released an image of a man they wish to speak to in connection with an incident on a late-night train from London Bridge last month.
Officers from the BTP are investigating after a woman was sexually assaulted by a man on a train traveling between London Bridge and Chislehurst stations.
Detectives have released an image of a man they would like to talk to about the incident which took place between 12.53am and 1.15am on Friday 18 July.
"The man followed the woman onto the 12.48am Charing Cross to Orpington service at London Bridge Station," said Detective Constable Andy Parkinson.
"He sat next to her and began to touch her inappropriately for a period of around 20 minutes before he left the train at Chislehurst station.
"There were a few people on the train at the time who may have thought the pair were a couple and were reluctant to step in.
"This was not the case and I am urging these people to come forward as they may have information crucial to our investigation."
"The man's behaviour was totally unacceptable and inappropriate and we are currently following several lines of enquiry.
"We are now releasing an image of man we want to speak to in relation to the incident. Please look closely at this picture. Do you recognise the man? If you do, please get in contact with us."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference B8/SSUB of 13/08/2014.
Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.