Your eye. The ultimate ID card

The PIN code of the future will be impossible to remember - yet you'll carry it everywhere. New cash machines will be able to read the pattern of your iris, uniquely and unforgeably identifying you. Charles Arthur, Science Editor, describes how Swindon is hosting a futuristic technology.

The head office branch of the Nationwide Building Society is to be the venue for a system which could eventually replace cash cards and the hassle of forgotten four-digit PINs _ personal identification numbers. An automated teller machine (ATM) will go into use next year which has an inbuilt video camera that can scan the user's iris for 250 key characteristics in its radial pattern, and determine within two seconds if the person is who they claim to be.

Like fingerprints, the iris offers a unique mark of identification. This could mark a breakthrough in the fight against fraud.

The new system, built by Sensar of New Jersey, compares the picture of the iris taken at the ATM with a previously stored image. It claims accuracy of better than 0.001 per cent and works even when the person is wearing contact lenses or glasses. It even works for blind people and those with cataracts. The only people for whom it does not appear to work are those born with a congenital form of blindness which leaves them without an iris.

Forgery is also impossible. Photographing the iris and sticking that on spectacles, or (gruesomely) taking out the eyeball would all fail, said Mike Magin, technology vice-president of Sensar, because the system detects the three-dimensions of the eye.

The system lights the iris, scans it with a video camera and then uses a computer to analyse the results. The extra cost is already less than $25,000 (pounds 15,250).

If the system could be miniaturised and condensed onto a single chip, it could be used to personalise many other consumer items, replacing house and car keys, and offering a guaranteed password for PCs.

The Nationwide trial is expected to last six months. Nationwide chief executive, Brian Davis, said: "it will be fascinating to test our customers' reaction to it." Tom Drudy, head of Sensar, said: "We think it will change the way people do banking."