Police are hunting a train flasher who stared at a passenger on a train to West Croydon while masturbating.

British Transport Police today released an image of a man sought following the "deeply distressing" indecent exposure, which happened between Streatham and Thornton Heath.

The victim, a woman in her 30s, boarded the train at Streatham on Saturday April 12. The man sat directly opposite her shortly after.

She was using her mobile phone when she realised the flasher was staring at her and masturbating.

She shouted at him and moved seats. 

The suspect got of the train at Thornton Heath, where he is believed to have boarded another to Norbury.

Det Cons Marie Jeffery said: "I am asking anyone who recognises the man in this picture to contact BTP as a matter of urgency, as we believe he will be able to help us in our investigation. We also want to hear from anyone else with information about what happened.

“This incident was deeply distressing for the victim and, while indecent exposure on the rail network is rare, we know they can be very upsetting for victims.

“That is why we treat them very seriously and work closely with train companies and local police forces to identify those responsible and take the appropriate action.”

Anyone with information about the incident can contact British Transport Police on 0800 40 50 40 or ring Crimestoppers anonymously on 0800 555 111, quoting reference number SSUB/B10 of 12/05/14.