In many US states, information is encoded in drivers' licences and can be used to find out a customer's age, while other businesses use the data forsecurity purposes

Last week, the Vintners' Federation of Ireland (VFI) called on Government to introduce a mandatory identity card to combat under-age drinking. Mr Richard Dunne, the president of VFI, warned that some publicans are hampered by being unable to accurately identify a patron's age.

Many states in the US have overcome this problem by having such information encoded in a driver's licence. The age limit for persons drinking alcohol is 21 and for buying tobacco it is 18. In the past decade, more than 40 states have issued drivers' licences with bar codes or magnetic stripes that carry standardised data such as name, address and birth date.

Two-dimensional bar codes that can store more data, such as eye colour, height, weight, sex, social security number and, in some instances, a biometric identifier, have been adopted by 30 states, including New York.

A driver's licence is carried by more than 90 per cent of US adults and is often used for identification purposes. Scanners that can read the information stored on these licences are popping up all over the country.

The ID-Check terminal, which is manufactured by Intelli-Check of Woodbury, New York, can check all data in one second, except for the person's height and photograph, which a doorman needs to verify for himself. It can automatically calculate the person's age and expiration date on the card. There's a manual option for unreadable and non-encoded IDs.

In most cases, as they enter a bar, patrons hand the doorman their driver's license who swipes it through a small black machine. If a licence is valid and its holder is over 21, a red light blinks and the patron can pass through. Not only are bars using such machines to detect fake IDs but, for security reasons, so are convenience stores, airports, hospitals, government buildings, car-rental companies, adult shops and casinos.

Mr James McCauley, president of 1 Touch Inc, based in Bohemia, New York, said he had sold 160 ID-Check units in Queens, Brooklyn, Nassau County and Suffolk County (two counties on Long Island) and that bars bought 95 per cent of the units.

"The machine removes human error and it gives the bar-owner proof that his staff did ID that person," he said.

New York state passed legislation in August 1999 that allows a retailer who faces a charge of selling alcohol or tobacco products to minors a defence in a court of law only if an electronic verification device was used in the sale.

In New York, businesses are only allowed to store name, birth date, driver's licence ID number and expiration date for the purpose of age verification.

The ID-Check machine can store up to 10,000 records (including the person's name and address) and, when a card is swiped, it does not publicly display the information but stores it locally within the machine, which is plugged into the wall, not a telephone line.

As the person's ID is verified, information pops up saying "alcohol yes", "tobacco yes".

Mr McCauley says the machine can detect fake IDs, like a fake New York state driver's licence, which can be bought online for about $150 (€163)) to $300. To the naked eye, these fake IDs look real enough as some even contain a photograph, a barcode and the state's hologram. But, the machine can detect the discrepancies and reject the card.

The ID-Check terminal, which costs $2,495, can not only verify a legal ID but will also process out-of-state IDs, military IDs, non-driver's licence IDs and international licences from Finland, South Africa and Canada, which use barcodes and magnetic stripes.

The only person who has access to all this personal information is the business owner and it can provide him with some valuable marketing tools.

For example, by using the records contained within the machine, a bar owner can compile a database that shows how many men and women drink on certain nights, what time they arrive, where they live and their age, and he can target his music bands or promotions accordingly.