| A part from the robotic voice nagging "please look into the mirror, please look into the mirror" as you line up your eye, it's absolutely painless. There's no flash, not even a click, as the hidden camera takes four digital snapshots of your iris.
Within three minutes your iris pattern - theoretically unique - is stored in a smartcard's memory chip. Short of stealing your eyeballs, no thief can pass themselves off as the legitimate card holder.
Iris-scan biometric security is one of the few James Bond technologies (Moonraker) to become reality. People applying in person for passports recently will have seen an iris-scanning machine at passport offices in London and Glasgow. It's there to test public attitudes to biometrics as part of a consultation into the government's planned "entitlement card".