Whether citizens like it or not, their governments are anxious to know everything about them.
There are plenty of technologies they can harness to this purpose. But the trick is to find a politically and culturally acceptable way to apply them.
The UK's controversial identity card and, more importantly, its associated National Identity Register, is a case in point. The government would like to have a single database that contains 49 items of information about each citizen.
The register would include biometric data such as fingerprints, facial images and until recently, iris scans, as well as biographic data such as name, date and place of birth, address, sex, nationality, entitlement to remain in the UK, as well as the particulars of everyone who supplies information to corroborate a person's identity.
Crucially, each person would have a unique identity number or token. Different database owners could use it to associate other data items with that identity. For example, in theory, if Land Registry and the Driver, Vehicles Licensing Authority both used your ID number to identify their records with you, HM Revenue & Customs could use it to see how many cars or properties you own and see if it was a reasonable reflection of your declared income.
Government agencies and private firms could then identify a person uniquely, monitor that person, and intervene when they wanted. For example, it could allow the Department of Work & Pensions to identify the 36% of pensioners the National Audit Office estimates are entitled to but not claiming social benefits and to ensure that they receive what they are due.
A number of polls, most recently one by Mori, have shown that eight out of 10 Britons have no objection in principle to ID cards. Indeed, 80% already have a passport.
Nevertheless, the government is walking through a political minefield over ID cards. Restricted documents on NIS roll-out plans have leaked from inside the Identity & Passport Service the prime minister has made equivocal statements over its future the opposition has threatened to scrap ID cards if it comes to power some MPs have said they would go to jail rather than accept it, polls show public support for the card is slipping, and the press is increasingly sceptical.
How might the government turn it around, and are there any examples it might learn from?
Europe, which has a long-standing tradition of identity documents, offers many examples. Estonia and Finland are both thought particularly successful, but each has special circumstances that do not apply to Britain. Instead, Hong Kong may provide some more pertinent examples.
When Britain handed Hong Kong back to China in 1998, the new government kept on the colonial identity cards that all Hong Kong residents carried by law. Crucially, it also kept the island's status as a free port. This made the right of abode highly desirable. The Hong Kong residents' card thus became a passport to privileges rather than a resented burden and intrusion on their privacy.
In developing a new smart card-based biometric identity card, the Chinese authorities made it easy for citizens to decide to enrol. Entering Hong Kong from the mainland remains a bureaucratic time-consuming nightmare for travellers. However, within 10 seconds readers at the border can scan a traveller's thumb prints, compare them with the images stored on the ID card and open the gates to the promised islands. Moreover, the cards are free and voluntary.
Small traders who cross the border often were the first to take it up. This spread to family and business partners. Soon enough cards were in circulation to make it attractive for the Hong Kong Post Office to add a free digital certificate application to the card. Card holders can now use this to authenticate online transactions such as gambling bets, open bank accounts, hire cars, rent flats and so on.
With the card even new immigrants can acquire a bank account, tax number and accommodation inside a day. They soon sign up.
The contrast with the mooted UK card is stark. Hong Kong offered residents a single obvious personal benefit - time saved at immigration control. The UK card has no such clarity.
According to a widely leaked document, the fundamental objectives of the National Identity Scheme are to improve the efficiency and effectiveness of border, immigration and labour controls, to cut serious crime committed using faked identities, and reduce the risk of terorist incidents. None represents a direct benefit to individuals.
In addition, the Hong Kong card simply verifies the unique identity of the card holder extra functions stem from market opportunities it creates. The UK card already appears blurred by bureaucratic function-creep. Its original purpose was to identify people (citizens) entitled to receive state benefits. This morphed into a national address register, and then into a crime-fighting tool.
Above all, the Hong Kong authorities have kept their citizens' goodwill by making enrolment voluntary. The residents and immigrants consent to give their details. The UK government has hinted it might force people to use its card. This has fuelled suspicion and resentment.
Is it too late for Gordon Brown to pull this rabbit from the hat? To do so he must make it possible for people to use the card, and only the card, as a sufficient proof of who they are. If one needs the card plus other evidence, why does one need the card at all?