Iris recognition software, one form of biometric identity verification, is a far surer method of security than PIN numbers and other password-protected systems, according to research conducted by Cambridge University.

Researchers at the university's computer department compared over 2,000 iris images and concluded the chances of two eyes being identical are 10 million to one.

Headed by one of the university's head researchers, John Daugman, the report team found that patterns in biometric systems are more distinctive than those found in fingerprints and are far more difficult to fake.

Even if only three-quarters of a person's iris matches the scan, according to the report, there is only a one in 10,000,000,000,000,000 (10 quadrillion) chance that it is someone else's eye.

Daugman claims not one single false identification was recorded across all the scans. His report rules out other worries that scanning eyes could prove harmful. It also debunks the notion that illness could make verification difficult.

"There is a popular belief that the iris systematically reflects one's health or personality, but such claims have been discredited as medical fraud," said Daugman.

Companies that have already implemented the biometric technology in the workplace include LG electronics and BT. Nationwide is currently trialling biometrics.