A businessman who sold fake bomb detectors around the world has been jailed for seven years.
The devices made by Gary Bolton, 47, were simply boxes with handles and antennae, the Old Bailey heard.
The prosecution said he sold them for up to £10,000 each, claiming they could detect explosives. The trial heard the firm had a £3m annual turnover selling the homemade devices.
Bolton, of Redshank Road, Chatham, Kent, had denied two charges of fraud.
As he passed sentence, Judge Richard Hone QC described the equipment as "useless" and "dross" and said Bolton had damaged the reputation of British trade abroad.
The court was told Bolton knew the devices - which were also alleged to be able to detect drugs, tobacco, ivory and cash - did not work, but continued to supply them to be sold to overseas businesses.
They were made at Bolton's home and the premises of his company Global Technical Ltd, near Ashford, and sold in more than a dozen countries, including Mexico and Thailand.
One purchaser X-rayed a device and found nothing inside the box, the court was told.
In 2010, a Home Office defence expert tested Bolton's GT200 detector at the request of the Office of Fair Trading and found it had "no credibility as an explosive detector" because it had no functioning parts.
Judge Hone said Bolton maintained the "little plastic box" was a piece of working equipment, selling it to scores of international clients - including for use by armed forces - despite evidence proving it was "useless".
"You were determined to bolster the illusion that the devices worked and you knew there was a spurious science to produce that end," he said.
"They had a random detection rate. They were useless.
"Soldiers, police officers, customs officers and many others put their trust in a device which worked no better than random chance.
"The jury found you knew this but you carried on. Your profits were enormous."
Jurors found Bolton guilty of a charge of making an article for use in the course of fraud and one of supplying an article for use in the course of fraud, between January 2007 and July last year.
The prosecution told the court Bolton had another fraudster's fake bomb detector in his house.
It was produced by James McCormick.
In a separate case, McCormick, 57, of Langport, Somerset, was jailed for 10 years in May for selling more than 7,000 fake detectors.
A confiscation hearing against Bolton is due to be held next year.
- This story was amended on 20 August to reflect the fact the name of Gary Bolton's company was reported in error as Global Technology Limited, which is not connected in any way to the defendant's company, Global Technical Ltd.