A BBC Newsnight investigation reveals that a "bomb detector" sold around the world and particularly to Iraq by a British company cannot possibly work.
Reporter Caroline Hawley took the central component of the "detector" - a card which it is claimed can detect explosives - to the Cambridge Computer Laboratory to be tested by Dr Markus Kuhn.
The managing director of a British company that has been selling bomb-detecting equipment to security forces in Iraq was arrested on suspicion of fraud today.
At the same time, the British government announced that it was imposing a ban on the export of the ADE-651 detectors because it was concerned they could put the lives of British forces or other friendly forces at risk.
The government promised to help investigate the multimillion-pound deal between the company, ATSC, and the security forces in Iraq.
Iraq has invested more than £50m in buying the devices and training people to use them. Police and military personnel have used them to search vehicles and pedestrians for explosives. But concerns over their effectiveness – and fears they could put lives at risk – have been raised.
Avon and Somerset police officers arrested Jim McCormick, 53, on suspicion of fraud by misrepresentation. A spokesman said: "We are conducting a criminal investigation and, as part of that, a 53-year-old man has been arrested.
"It was reported to the Chief Constable Colin Port, through his role as the Association of Chief Police Officers' lead on international development.
"Given the obvious sensitivities around this matter … we cannot discuss it any further at this time."
The export ban on the device will come into force next week.
McCormick, managing director of ATSC, based in a former dairy in Sparkford, Somerset, defended his devices last year.
He claimed they were derided because of their flimsy appearance and said the detectors pinpointed explosives in the same way a dowsing rod finds water.
Speaking then, he said: "We have been dealing with doubters for 10 years. One of the problems we have is that the machine does look a little primitive."
The focus on the devices has intensified over recent weeks following co-ordinated waves of bomb attacks in Baghdad.
ATSC's brochures claim the device can detect minute quantities of explosives at large distances – up to 1km.
There are no batteries in the device. It consists of a swivelling aerial mounted to a hinge on a hand grip.
The American magician and professional sceptic, James Randi, tested the devices and expressed his doubts over them. He even challenged McCormick to prove the ADE-651 really worked – offering $1m if he succeeded.
McCormick once told the BBC that "the theory behind dowsing and the theory behind how we actually detect explosives is very similar."
A spokesman for the Department for Business, Innovation & Skills said: "Tests have shown that the technology used in the ADE-651 and similar devices is not suitable for bomb detection. As non-military technology, it does not need an export licence and we would not normally need to monitor its sale and use abroad.
"However, it is clearly of concern it is being used as bomb-detection equipment. As soon as it was brought to the attention of the Export Control Organisation and Lord Mandelson, we acted urgently to put in place export restrictions which will come into force next week.
"We will be making an order, under the Export Control Act 2002, banning the export of this type of device to Iraq and Afghanistan.
"The reason the ban is limited to these two countries is that our legal power to control these goods is based on the risk that they could cause harm to UK and other friendly forces.
"The British Embassy in Baghdad has raised our concerns about the ADE-651 with the Iraqi authorities. We have offered co-operation with any investigation they may wish to make into the how the device came to be bought for their military as bomb-detection equipment."
Despite major bombings that have rattled the nation, and fears of rising violence as American troops withdraw, Iraq’s security forces have been relying on a device to detect bombs and weapons that the United States military and technical experts say is useless.
The small hand-held wand, with a telescopic antenna on a swivel, is being used at hundreds of checkpoints in Iraq. But the device works “on the same principle as a Ouija board” — the power of suggestion — said a retired United States Air Force officer, Lt. Col. Hal Bidlack, who described the wand as nothing more than an explosives divining rod.
Still, the Iraqi government has purchased more than 1,500 of the devices, known as the ADE 651, at costs from $16,500 to $60,000 each. Nearly every police checkpoint, and many Iraqi military checkpoints, have one of the devices, which are now normally used in place of physical inspections of vehicles.
Millionaire businessman James McCormick, 56, has been convicted at the Old Bailey of three counts of fraud after selling fake bomb detectors. The Advanced Detection Equipment was based on a golf ball finder device and sold for up to $40,000 (£27,000) in Iraq, Georgia, Saudi Arabia and Niger. McCormick, of Langport, Somerset, said to have made £50m from sales of the devices, will be sentenced next month. An Iraqi bomb victim described him as a "morally bankrupt" man.