Remember, they are always watching you. Use cash when you can. Do not give your phone number, social-security number or address, unless you absolutely have to. Do not fill in questionnaires or respond to telemarketers. Demand that credit and data-marketing firms produce all information they have on you, correct errors and remove you from marketing lists. Check your medical records often. If you suspect a government agency has a file on you, demand to see it. Block caller ID on your phone, and keep your number unlisted. Never use electronic toll-booths on roads. Never leave your mobile phone on--your movements can be traced. Do not use store credit or discount cards. If you must use the Internet, encrypt your e-mail, reject all "cookies" and never give your real name when registering at websites. Better still, use somebody else's computer. At work, assume that calls, voice mail, e-mail and computer use are all monitored.

This sounds like the paranoid ravings of the Unabomber. In fact, it is advice being offered by the more zealous of today's privacy campaigners. In an increasingly wired world, people are continually creating information about themselves that is recorded and often sold or pooled with information from other sources. The goal of privacy advocates is not extreme. Anyone who took these precautions would merely be seeking a level of privacy available to all 20 years ago. And yet such behaviour now would seem obsessive and paranoid indeed.

That is a clue to how fast things have changed. To try to restore the privacy that was universal in the 1970s is to chase a chimera. Computer technology is developing so rapidly that it is hard to predict how it will be applied. But some trends are unmistakeable. The volume of data recorded about people will continue to expand dramatically (see pages 21-23). Disputes about privacy will become more bitter. Attempts to restrain the surveillance society through new laws will intesify. Consumers will pay more for services that offer a privacy pledge. And the market for privacy-protection technology will grow.

Always observed

Yet here is a bold prediction: all these efforts to hold back the rising tide of electronic intrusion into privacy will fail. They may offer a brief respite for those determined, whatever the trouble or cost, to protect themselves. But 20 years hence most people will find that the privacy they take for granted today will be just as elusive as the privacy of the 1970s now seems. Some will shrug and say: "Who cares? I have nothing to hide." But many others will be disturbed by the idea that most of their behaviour leaves a permanent and easily traceable record. People will have to start assuming that they simply have no privacy. This will constitute one of the greatest social changes of modern times.

Privacy is doomed for the same reason that it has been eroded so fast over the past two decades. Presented with the prospect of its loss, many might prefer to eschew even the huge benefits that the new information economy promises. But they will not, in practice, be offered that choice. INstead, each benefit--safer streets, cheaper communications, more entertainment, better government services, more convenient shopping, a wider selection of products--will seem worth the surrender of a bit more personal information. Privacy is a residual value, hard to define or protect in the abstract. The cumulative effect of these bargains--each attractive on their own--will be the end of privacy.

For a similar reson, attempts to protect privacy through new laws will fail--as they have done in the past. The European union's data protection directive, the most sweeping recent attempt, gives individuals unprecedented control over information about themselves. This could provide remedies against the most egregious intrusions. But it is doubtful whether the law can be applied in practice, if too monay people try to use it. Already the Europeans are hinting that they will not enforce the strict terms of the directive against America, which has less stringent protections.

Policing the proliferating number of databases and the thriving trade in information would not only be costly in itself; it would also impose huge burdens on the economy. Moreover, such laws are based on a novel concept: that individuals have a property right in information about themselves. Broadly enforced, such a property right would be antithetical to an open society. It would pose a threat not only to commerce, but also to a free press and to much political activity, to say nothing of everyday conversation.

It is more likely that laws will be used not to obstruct the recording and collection of information, but to catch those who use it to do harm. Fortunately, the same technology that is destroying privacy also makes it easier to trap stalkers, detect fraud, prosecute criminals and hold the government to account. The result could be less privacy, certainly--but also more security for the law-abiding.

Whatever new legal remedies emerge, opting out of information-gathering is bound to become ever harder and less attractive. If most urban streets are monitored by intelligent video cameras that can identify criminals, who will want to live on a street without one? If most people carry their entire medical history on a plastic card that the emergency services come to rely on, a refusal to carry the card could be life-threatening. To get a foretast of what is to come, try hiring a car or booking a room at a top hotel without a credit card.

Click here for related Economist article on pp. 21-23