The only way to trace a terrorist is through biometrics," Mike Kirkpatrick, assistant director of the FBI's criminal justice services division, told a conference for European firms selling biometric security measures yesterday. "[Traditional] passports are pretty damn meaningless."

The FBI, which has more than 75m fingerprints on its criminal and civil computer records, is adding biometric details from suspects detained in Iraq, Afghanistan and elsewhere. "We are obtaining DNA from terrorists around the world as we encounter them," Mr Kirkpatrick said. "We have set up a terrorist screening centre. In Iraq, the high value detainees are having DNA samples, fingerprints and digital photographs taken. The numbers involved are in the thousands. We are doing it wherever it's appropriate, wherever there's a threat to the USA."

At least there's one voice of reason out there, although we don't know if anyone's listening:

There is now a total obsession with this technology as a way of combatting anything and everything and it's a fallacy," said Barry Hugill of Liberty. "Once you begin to compile massive databases it's a matter of common sense that you are going to get the most horrendous mix-ups, with the wrong people being accused and the the wrong information being shared around the world."

The biometric business is booming. Here's some examples, in case you are looking for some stocks to avoid on civil liberties grounds:

Californian biometric company IriTech Inc offers an iris-scanning programme to detect drug use. By analysing the pupil's reaction to a flash of light, the programme claims, it can "track the acute irregularities of the nervous system". Used by probation services to monitor the presence of drugs in the body.

3D facial recognition is being championed as a means of overcoming the problems experienced by computer analysis of faces. Recognition Sciences claims it can assemble a three-dimensional image of a suspect given just two photographs from different angles.

In Britain, a company called Unilink is putting fingerprint scanning systems into an immigration detention centre near Heathrow to control visits.