Vigilantes who took the law into their own hands when a London Underground passenger exposed himself in front of children could face arrest, according to reports.
Footage posted online shows the man dropping his trousers on a Hammersmith and City line train at around 3.30pm on Thursday.
When challenged by commuters on the eastbound service at Upton Park station, a fight erupts.
Up to four men stepped in when he repeatedly refused to pull up his pants and began shouting repeatedly “f*** off”.
British Transport Police believe the naked suspect, who has since been detained under the Mental Health Act, was assaulted by them.
Detective appealed for witnesses to the incident but there have been no arrests over the brawl.
A spokesman said: “Officers were called to reports of a man exposing himself on the District Line at East Ham Underground station.
“The man had been assaulted by a number of other passengers and was initially arrested by an off duty officer, before being detained under the mental health act and taken to hospital.
“An investigation into the incident is ongoing.”
When the suspect swears, one commuter can be heard replying: “What do you mean f*** off? You need to get off the f***ing train. Now. There are kids on here.”
The naked man continued to shout and wave his belt before more passengers stepped in to restrain him.
A fight then appeared to break out, with the group punching and kicking him to the floor of the carriage.
He was seen with his hands forced behind his back before being unceremoniously thrown off the train by several men.
A photograph later showed him pinned to the ground on the platform at East Ham station, where passengers waited with him for help to arrive.
