The Independent UK reports:

The explosive device smuggled in the clothing of the Detroit bomb suspect would not have been detected by body-scanners set to be introduced in British airports, an expert on the technology warned last night.

The claim severely undermines British PM Gordon Brown’s focus on hi-tech scanners for airline passengers as part of his review into airport security after the attempted attack on Flight 253 on Christmas Day.

The Independent on Sunday has also heard authoritative claims that officials at the Department for Transport (DfT) and the Home Office have already tested the scanners and were not persuaded that they would work comprehensively against terrorist threats to aviation.

The claims triggered concern that the Prime Minister is over-playing the benefits of such scanners to give the impression he is taking tough action on terrorism.

And experts in the US said airport “pat-downs” – a method used in hundreds of airports worldwide – were ineffective and would not have stopped the suspect boarding the plane.

Umar Farouk Abdulmutallab, 23, allegedly concealed in his underpants a package containing nearly 3oz of the chemical powder PETN (pentaerythritol tetranitrate). He also carried a syringe containing a liquid accelerant to detonate the explosive.

Since the attack was foiled, body-scanners, using “millimetre-wave” technology and revealing a naked image of a passenger, have been touted as a solution to the problem of detecting explosive devices that are not picked up by traditional metal detectors – such as those containing liquids, chemicals or plastic explosive.

But Ben Wallace, the Conservative MP, who was formerly involved in a project by a leading British defence research firm to develop the scanners for airport use, said trials had shown that such low-density materials went undetected.

Tests by scientists in the team at Qinetiq, which Mr Wallace advised before he became an MP in 2005, showed the millimetre-wave scanners picked up shrapnel and heavy wax and metal, but plastic, chemicals and liquids were missed.

If a material is low density, such as powder, liquid or thin plastic – as well as the passenger’s clothing – the millimetre waves pass through and the object is not shown on screen. High-density material such as metal knives, guns and dense plastic such as C4 explosive reflect the millimetre waves and leave an image of the object.

(Source: Independent UK)