The reason is that travel is going all biometric and, if the technology works as planned, it will be a computer rather than a human that checks your photo.

Not to be confused with biorhythms, biometrics is the science of identifying individuals from their unique biological properties, such as fingerprints, the patterns on their irises or the arrangement of the features on your face and the new generation of passports will include digitised biometric information on an embedded computer chip.

The need to correctly identify travellers has taken on greater urgency since September 11th and the US government is at the forefront of implementation of biometric identification procedures. Since the end of October, all visitors to the country have had their photo taken and their fingerprints scanned. It has also set a deadline of October next year for the requirement for visitors from all countries to have biometric identifiers included in their passports.

But this does not mean everyone in the US will have a biometric passport.  Certain government employees will start to be issued with biometric passports in December while the general public will begin to receive them in the first few months of 2005. By the end of 2005, all new US passports issued domestically will be biometric passports.

Denmark is likely to be the first country to issue the general public with biometric passports. The Danish government has signed a contract with supplier Setec to issue three million passports over the next five years.

Australia was one of the first movers in the introduction of biometric passports. In November 2002, it issued more than 3,000 members of Qantas' aircrew with biometric passports containing facial biometrics.

During a two-month pilot programme, 10,000 identity checks were performed. Participants entered a kiosk and had their face compared to that on the stored image. The process took typically less than 10 seconds. The trial is now being extended to a second international airport and to selected passengers as well as aircrew.

To ensure everyone's passport is readable in any country, the International Civil Aviation Organisation (ICAO) has developed an international standard for biometric passports. The organisation carried out a comprehensive analysis of what biometric information should be included on a passport and concluded that facial recognition was better than both fingerprints and iris scans for the purposes of passports. Passports that meet ICAO's standard will therefore include facial biometrics as the primary means of identification and at least one other.

Facial recognition involves measuring the distance between key points on the face. These measurements are unlikely to change if you are wearing glasses one day, have grown a moustache or have changed your hairstyle.

The UK Passport Service says it plans to introduce the UK's first biometric passports, which meet the ICAO standard, in late 2005 or early 2006. As part of the process, it has announced new guidelines for passport photographs to facilitate their conversion into biometric data. This means that for new passports, the face on the photo must cover 70-80 per cent of the photograph and should show the subject looking directly at the camera with a neutral expression and with their mouth closed. The photo must also be taken against a white, cream or light grey plain background.

However, when you first receive your new biometric passport, you may not notice much difference.

Denmark's new biometric passports include an information page made from a flexible plastic. As well as the holder's photograph and personal details, a "contactless" computer chip is embedded into the page, making it look virtually indistinguishable from an existing passport page.

Christophe Duverne, vice president of sales and marketing at Philips Semiconductors, which manufactures contactless chips, says: "The chip can be embedded in the cover or in the data page and the data page can be made from paper or polycarbonate."

Contactless systems will be familiar to anyone who has been issued with security passes that just needs to be waved in front of a reader to gain entry and also with users of London Underground's new Oyster cards which use Philips contactless chips. The contactless chip incorporates an antenna that picks up a radio signal generated by the reader.

Perhaps the only difference many will notice is the price. Applying for a standard UK passport currently costs £42. The Home Secretary David Blunkett recently told a Home Affairs Select Committee that new biometric passports are likely to cost around £70. The Home Secretary pointed out that without biometric passports, UK travellers would need to obtain a US visa. "It will cost an individual US$100 a time to obtain a visa and six weeks of considerable wait to do so," he said

Given that these new passports will include your biometric data, is there any need for a passport photo at all? For all of us sporting outdated haircuts in their passports, the answer is unfortunately still yes.

Like any technology, biometric identification is not entirely reliable and a passport may be rejected for any number of reasons.

Contactless chips are not entirely foolproof but Christophe Duverne at Philips is not worried about reliability. "We have shipped several hundred million contactless chips and they carry out millions of transactions every day in transport applications. The technology has been around for many, many years so we're not going into new territory here."

The other potential problem is that your face on the day you arrive at the airport may not be a good enough match with what is stored on your passport's chip. Until these teething problems are sorted out, we may still have to put up with the occasional smirk at customs.

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