Police have launched an appeal after a man exposed himself on a train.
The man boarded the train travelling between Surbiton and Clapham Junction during the early hours of November 30 last year.
He sat opposite a 27-year-old woman and exposed himself, while performing an indecent act as he stared at her.
Police have been circulating images of the suspect and spoke to local neighbourhood teams, but have been unable to find the culprit.
Police Constable Mark Payne said: "Although incidents like this are rare on the rail network, this was clearly a very frightening and upsetting ordeal for the victim and we’ll do all we can to arrest the person responsible.
"As part of our investigation we’ve issued CCTV of a man we believe may have information about this incident and are asking for the public’s help to name him. If you think you recognise this man, please contact us."
Anyone with information can call British Transport Police on 0800 40 50 40 quoting reference BX/LSA of 5/02/13, or Crimestoppers anonymously on 0800 555 111