A pervert who pleasured himself in front of shocked London Underground passengers has been warned he faces jail.

Devadas Ronald-Uthayakumar, 48, openly played with himself twice in front of horrified travellers on the Metropolitan Line.

Prosecutor Stella Waata said he boarded a train between Northwick Park in Brent and Pinner station shortly before 10pm on March 20 2015.

"Mr Uthayakumar got onto the train and sat opposite the complainant" she said.

"He placed a bag on his lap and began masturbating his penis which was fully exposed and out of his clothing.

"While doing so he used his bag to block his actions from other passengers in the carriage while still exposing himself to her."

She added: "The complainant made an attempt to film his masturbating actions on her mobile phone.

"This was partly successful in that she managed to film his actions but not his face."

Fled the scene with his manhood exposed

Ms Waata said the married father-of-two targeted another victim at midnight between Harrow-on-the-Hil l and Northwood station.

She said: "The defendant boarded the train and sat opposite her.

"She then became aware of him masturbating and his penis was exposed."

A week later he exposed himself to another female passenger between Euston Square and North Harrow station, Hammersmith Magistrates Court heard.

He was photographed by the victim before fleeing the scene with his manhood exposed.

According to the prosecutor, Uthayakumar leaned forward and made a grunting noise after sitting opposite the victim, before getting up to move with his testicles still hanging out a hole in his trousers.

All three women reported the incident to police and Uthayakumar was arrested. He pleaded guilty to three counts of outraging public decency on March 10.

District Judge Karim Ezzat said: "There was a degree of sophistication in as much as you were trying to conceal your actions from others while targeting individuals on trains.

He continued: "I take the view that the powers of this court are insufficient for sentencing, therefore I will commit your case to Isleworth Crown Court."

Uthayakumar, of St Thomas Drive, Pinner, was released on conditional bail ahead of sentence at Isleworth Crown Court on April 28.

He is barred from travelling on the tube after 10pm and must only travel with a pre-registered oyster card.