The A to Z of ID cards

B is for Biometrics

The ID cards project will use biometrics - unique physical characteristics - to identify card holders.

The ID cards will electronically store two fingerprints and a photograph on a built-in microchip, while the National Identity Register (NIR) will store all 10 fingerprints and a facial scan.

These details will be recorded when a person applies for a card. The original plan was to use 13 biometrics: 10 fingerprints, both irises and the face.

Government agencies and businesses can then confirm someone's identity by checking these biometrics, which the government argues will make identity fraud much harder.

Anyone trying to make a major financial transaction, for example, could have their biometric data on the card checked against the NIR. If they were not the registered cardholder this check would fail, the government claims.

However, trials of biometrics have shown that the technology is not without its problems.

It is harder to record the fingerprints of certain groups such as the elderly - and not everyone can provide them all.

As of February 2009 fingerprints and facial scans for foreign nationals were being captured at seven UK Border Agency centres, Armagh, Birmingham, Cardiff, Croydon, Glasgow, Liverpool and Sheffield.