A revolutionary material could prevent 'pass-by' cloning of passports and payment cards and improve pen interfaces, according to the UK developer.

Peratech director Philip Taysom points out that biometric and banking details in RFID modules can be read by powerful scanners held by someone walking past you, or standing behind you in a queue.

"People don't realise how vulnerable these things are. RFID used to be used for only transferring trivial data like product numbers in warehouses. Now it is being used payments and biometrics. Yet you can go on eBay and buy a scanner that will read the data for as little as £15."

Even the latest US passports, which have screening in their covers, are not immune because they tend to fall half open in your pocket, he says.

Peratech has developed a class of materials known as Quantum Tunnelling Composites (QTC), which are basically a polymer impregnated with conducting particles. Under normal circumstances these are insulators but when stressed, either by applied pressure or by twisting or tugging, they conduct electricity at the point of stress.

Their characteristics can be altered for different applications. A touchpad or digitiser tablet can use a QTC that changes resistance smoothly with pressure to provide the kind of tone gradation you would get with a pencils

Other QTCs act like pressure switches that are either on or off – and the switch may be as thin as 70 microns, and can be screen printed on to devices and cards.

Taysom said this makes them a very cheap way to protect RFID-enabled passports and cards. The RFID module could be switched off when not needed, and when you got to passport control it could be activated simply by pressing a switch point marked on the page.

The materials have many other uses, including monitoring structures for stresses and iPod switches woven in the fabric of clothes. The QTCs can survive repeated washing.

Peratech has yet to produce a transparent QTC. "We are working on that," says Taysom. But they are being used for PDA pen input, with a QTC strip round the display that sensing stresses in the screen window.