An Indian national has been arrested for installing hidden cameras across shower rooms and toilets in his office and coffee shops in London to film thousands of unsuspecting people. He has now been sentenced to four years in jail by a UK court.

George Thomas, a 38-year-old ex-manager with Ernst & Young, is accused of installing recording devices in the shower rooms and lavatories at his work place. He also reportedly installed them across washrooms in a large number of coffee shops in central London, says an Independent report

Thomas, who is married and has a child, is suspected of having filmed over 3,500 people over the course of almost six years. Among those he filmed include children and he started secretly recording people sometime in 2009, the London Crown Court revealed this week.

Thomas filmed people in coffee shops, then match images with recordings from the toilet and would make compilation videos for his sexual gratification, reports The Telegraph.

He was caught when a female employee at the office found a device in the shower room. The police found a memory card with visuals that showed Thomas’s face while he was placing the device, reports the Daily Mail. Officers then went to the nearest coffee shop and discovered a second camera hidden in the customer toilet. Thomas was identified as the suspect in the footage and arrested.

"This case is undoubtedly a sophisticated, organised, planned and long-running campaign of voyeurism the scale of which, the court is told, is beyond any previously encountered by the Metropolitan Police," said Judge Jeremy Donne.

The prosecution said some victims were filmed in their own homes or bedrooms and that some of Thomas' former colleagues now feel anxious and vulnerable using the bathroom at work.

Besides a four-year jail term, Thomas has been given a "Sexual Harm Prevention Order" for 10-years and will remain on the sex offenders' register for life.

The London police said they've never seen a voyeurism case that had such a wide scope. Detective Constable Sarah Gardner said "The images of unsuspecting people going about their daily business, and having their privacy breached in this way was appalling".

"Thomas' offending was extraordinary, not just because of the sheer numbers of people he filmed but also due to the highly organised way, in which he saved, stored and filed the footage," she said.

(with PTI inputs )