If successful, it could mean passengers need never wait in immigration queues, or have to remember their passports and visas. A trial will begin in October involving up to 2,000 North Americans who frequently use British Airways or Virgin Atlantic to fly to the UK.
The recognition technology works by training a video camera on the iris, the coloured part of the eye surrounding the dark pupil.
Each person has a pattern in their iris as distinct as their fingerprint. Unlike the retina - the light sensitive tissue at the back of the eyeball - the iris does not change with age or need to be scanned using intrusive infrared light.
The procedure takes less than a few seconds using a camera two feet away. It can be fully computerised with voice prompts and auto focus.
Powerful software then translates the iris pattern into a passport number, and exchanges the information with airport and airline computers to simplify checking in, luggage handling, boarding and passport control.
A spokesman for Heathrow said the project was part of a drive to simplify and speed up passenger travel. It has the backing of the Home Office's immigration service, which will pre-authorise those taking part in the scheme.
A similar trial is under way in the US at Charlotte airport in North Carolina. Hans Shrieber, senior vice-president of Eye Ticket Corporation, said yesterday that close to 500,000 travellers had used the scanners without an incorrect reading since his firm installed them in May last year.
The scope of the Heathrow experiment is, however, much broader since it deals with immigration and ticketing - a world first for a airport.
John Daugman, the Cambridge scientist who developed the mathematical algorithms used in the technology, said yesterday that biometric identification systems such as iris recognition would become increasingly popular.
"The trouble with traditional methods of identification is that they are based on special possessions, such as keys, or special knowledge, like passwords, but they only prove that the possession or knowledge was present at the time of the transaction," he said.
Recent trials conducted by the government's communica tions-electronics security group, pitted rival biometric systems such as face, fingerprint and hand identification, against iris recognition.
In 2.75m tests iris recognition recorded no false matches, compared with a rate of 10-25% for the other methods. It failed to make any match in 1.8% of cases on the first attempt but that fell to zero on the third.
Roger Bingham, a spokesman for Liberty, said the group had no problem with iris recognition if it were used in the same situation as a passport, but feared its use for domestic travel could amount to "a national identity scheme by the back door".
