Nicholas Jones: Identity cards will rule our lives: just ask the Spanish

Did you take part? Yesterday was the last day in the national debate to see if we want identity cards. "The public must help us decide," the Home Secretary insisted last July when he launched a "consultation exercise" to argue this thorny subject. Yet it's far more likely you never knew this was taking place, for, despite David Blunkett's wishes, it has failed to stimulate any debate. Even more astonishing has been its complete failure to show people what life would be like here if we were to get such cards.

Even Mr Blunkett's consultation paper saw the need to do this. It states that "people will be able to make a more informed decision... if they had a clear view as to how a scheme might work in practice". Yet he admitted last month that focus groups keep finding that people are confused about what identity cards would be for. Now that he is promising a draft Bill to launch them, the least he can do is show the public a working model, to help them to decide if they want the cards as much as he does.

This would hardly be difficult, when Europe offers such perfect examples. Maybe the reality of life with identity cards is not something Whitehall mandarins want exposed. However, it's no secret to those of us who live in Europe, where they are an everyday item.

Spain has a card very like Mr. Blunkett's proposed version. It astonished my Spanish wife to learn that Britain did not already have identity cards, for she has used one since she was 14. Our life in Madrid, by contrast, would simply stop without it. It has shown me how identity cards create a culture that is both absurd and intrusive.

Spain's card is a documento nacional de identidad or DNI, three letters integral to Spanish life. It carries personal details and an encrypted fingerprint, but its key feature is its unique number, which it shares with the holder's passport, driving licence and tax files. It is this element of the card that Whitehall most wants.

Most European identity cards date from periods of war or instability, and Spain's is a legacy of Franco. To be fair, Spanish police (unlike in France) no longer demand to see cards without reason. But almost everyone else does.

Initially the state bureaucracy made showing one's card a precondition for dealing with it. Today, it is business that increases the reach of identity cards. Spaniards have long needed them to open bank accounts; now they are vital for any credit-card purchase, and bureaux de change won't serve you without them. It's also impossible to buy a mobile telephone without theDNI, for the network will log its number with that of the phone. I guess the police can see such records: they are certainly told who is checking into Spanish hotels, since Spaniards must show their DNI. The hotel passes its number straight to the police.

Employers love identity cards. They photocopy the DNIs of new staff, whose payslips then carry the number for tax purposes. This, linked to bank records, allows the authorities to track individuals all through Spain's financial system. What really amazes me is the way Spain's card is needed for such harmless activities as renting a car or flat – or getting married. Our church did not read the banns but instead asked for DNI numbers. Even the nursery school expected to see it before taking our child.

When I ask Spaniards "Why?", they seem surprised. Then I remember that at 14 they all had to visit their local police station to be fingerprinted and photographed before receiving their first DNI card. It's a rite of passage that makes young Spaniards feel grown up, yet the first time they use their card is to sit school exams. Many will argue that such obsessive bureaucracy is cultural and could never come to Britain, but I predict it will. In Spain, British giants such as Barclaycard and Vodafone already ask to see customers' identity cards and will do so here.

The benefits Mr Blunkett believes identity cards will bring are hard to spot. His claims that they will cut crime, illegal working and immigration would astound Spaniards, who draw no connection between the DNI and crime prevention. They know the best crooks all carry forged cards: how, otherwise, could they open bank accounts to launder their loot ?

Spain's black economy thrives despite the DNI. In Recoletos, Madrid's swanky shopping district, the sidewalks seem paved with bootleg CDs being sold by African street vendors. Many are illegal immigrants but while people want cheap music, they are tolerated.

Spain's DNI does not produce Mr Blunkett's benefits, so it seems natural to ask Spaniards what exactly the point of it is. Why, they reply, to do all the things that would be impossible if one did not have one! It is the ultimate bureaucratic tool that makes Spain a highly monitored society under its lax facade. It is really a passport to live in Spain.

Continental experience shows that identity cards will dramatically change life in Britain. It also reveals why Whitehall really wants them. The daily logging of their unique card numbers will create audit trails that lead to that Blairite dream, joined-up government! This already exists in Europe because entire populations dutifully troop along to acquire identity cards, just because they always did. I wonder how Mr Blunkett will force 50 million-odd Britons to do likewise.

The author is a television producer who lives in Spain