A Kent businessman turned over £3million a year selling useless bomb detectors to security forces around the world, a court heard.

Gary Bolton, from Chatham, claimed his GT200 device could find explosives, drugs, cash, tobacco and even ivory at a distance of more than two miles.

But the detector was actually nothing more than a retractable antenna mounted on a plastic box, jurors were told.

Bolton – who admitted he has no background in science or security – became involved in marketing and selling bomb detectors in the late 1990s.

The 47-year-old, of Redshank Road, St Mary's Island, then brought out the GT200 through his Ashford-based business Global Technical.

Prosecutor Richard Whittam QC told the Old Bailey he claimed it was "capable of detecting a mere trace of a substance".

"The device was nothing more than a box with a handle and an antenna attached to it..." - Richard Whittam QC, prosecuting

He said: "The device could be sold for about £10,000 per handset with £3,000 commission going to the agent.

"In fact the device was nothing more than a box with a handle and an antenna attached to it."

They were sold to countries across the world, including Mexico and Thailand, and were tested by British American Tobacco and the Royal Dutch Navy.

Mr Whittam added: "Despite the allegation they did not work, a great number of people did buy them. Gary Bolton made considerable sums of money."

The prosecution suggest Bolton faked a report about the GT200 to market the device.

Police searched his office, in Moat Way, Sevington, in June 2010 and recovered £40,000 as well as boxes, manuals and components.

Bolton admitted he had made the GT200 and was responsible for selling them around the world.

Bolton, who claims the GT200 did work and he was not acting dishonestly, denies fraud by false representation and making or supplying an item for use in fraud.

The trial continues.