Police have launched an appeal to find a man who exposed himself to a woman on a Docklands Light Railway train and masturbated in front of her.

The pervert then followed the 28-year-old victim off the carriage before she managed to escape.

Officers said the man approached the victim at Westferry station at 10pm on Monday. March 2.

Detective Constable Suleman Yazdani said: “Once on the train, he sat opposite her, exposing himself and masturbating, before standing up and making lewd remarks.

“The woman tried to ignore him and hurriedly left the train at Tower Gateway. Undeterred, the man followed her off the train, before eventually leaving the station via the main exit and making his way towards Tower Hill London Underground station.”

Police have viewed CCTV footage of the incident and released an image of a man they want to speak to.

DC Yazdani said: “We will not tolerate this disgusting and frightening behaviour, and I am pleased that the victim reported this incident to us.

“BTP is committed to eradicating all forms of unwanted sexual behaviour from the rail network, but we need the public’s help.

“I am confident the man in this image can assist with our investigation. Please tell us who he is.”

Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference TSUB/B7 of 12/03/2015. Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.