An investigation has been launched after a man was caught urinating on the seat of a train.

British Transport Police launched an enquiry into the incident, which took place on a Central line train at Loughton tube station on Friday at 4.30pm, after a video was posted online showing a man urinating on a seat in the corner of a carriage.

The video, which was shot by vigilante cyclist Dave Sherry, shows the man, who is wearing black trousers, a black hooded jumper and a black cap, kneeling on the seat with his back to the carriage before sitting down and placing his feet up.

He is also seen spitting on to the floor of the carriage before leaving the train at Epping and getting into a silver Volkswagen Golf with two other men.

Mr Sherry, whose video has already had more than 300 views, said: "it is repulsive and dirty.

"At first I thought he was urinating into a bottle but then I saw the seat and it was soaked. It really is disgusting.

"I wanted to ask him why he thought it was OK to do something like that but he was with friends and I was outnumbered if anything was to happen.

"Passengers do not need to tolerate this kind of behaviour.

"I warned the driver when I got off as I didn't want anyone to sit in it.

"I got off at the same station and made sure I captured the number plate of his vehicle as he needs to be punished.

"It is such a dirty act and completely disgusting. I was repulsed."

Transport for London deputy director of enforcement operations, Siwan Hayward, said: “We work hard with our policing partners to ensure our network remains a safe and secure environment for all our passengers.

"We have a zero tolerance attitude towards any acts of indecency on our network and will work with the BTP to investigate this incident.”

A spokesman for British Transport Police said: “We have been made aware of a video purporting to show a man urinating in the corner of a Central line train carriage.

“Officers are now viewing the footage and making enquiries to establish a fuller picture of the incident and when it took place."

Anyone with any information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference 496 of 03/04/2015.