A pervert followed a woman into the toilets of a station and performed a sex act in front of her, police said.
The man made lewd suggestions to the woman in her thirties and then exposed himself despite the woman rejecting his advances, according to detectives.
He is then said to have blocked her from leaving the toilets at Finsbury Park station in north London at around 11am on Thursday, October 9.
Police today released a CCTV image of a man wanted in connection with the "extremely disturbing" ordeal.
Detective Constable Gerard Hughes said: “A woman in her thirties was approached by a man on the platform.
“He began making lewd suggestions and, despite the victim making it clear she did not want to engage with him, the man followed her into the women’s toilet on platform 7.
The man subjected the woman to a frightening ordeal in which he performed a sex act in front of her, police said.
“The woman tried to leave the toilet, but the man blocked her way.
“Thankfully, a member of station staff, who saw the man follow the woman, banged on the door, after which the man fled the station.”
He added: “This was an extremely disturbing incident, which, unsurprisingly, caused considerable distress to the victim."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference ESUB/B5 of 10/11/2014. They can also contact Crimestoppers anonymously on 0800 555 111.
