Police have appealed for witnesses after a man indecently assaulted a passenger on a morning commuter train between Clapham Junction and Norbury.

The man, described as having "distinctive scarring to his face", approached a 26-year-old woman in the first carriage of train and "touched her inappropriately".

The assault took place just before 7.50am on the 7.38am service to Epsom Downs via Sutton on Friday, August 21.

British Transport Police today released details of the attacker in a bid to trace him.

PC Mark Luker said: "The woman sat in the first carriage of the train and was approached by a man who had tried to have a conversation with her at Clapham Junction station.

"As the journey continued the man approached the woman and touched her inappropriately. She confronted him and he moved away.

"Though the victim wasn’t physically injured during the incident, she was extremely frightened by the man’s actions and is still finding it difficult to come to terms with what happened."

The man was white but dark-skinned, slim and between 5ft 6ins and 5ft 10ins tall. He had short black hair and facial scars and is thought to have been between 30 and 40 years old.

PC Luker said: ""I am confident someone will recognise this description and am calling on the public to come forward and help trace him.

Anyone with information is asked to call British Transport Police on 0800 40 50 40 or Crimestoppers anonymously on 0800 555 111, quote log number SSUB/B5 of October 13, 2015.