One of the main objections to identity cards, whatever the technology, is that they will inevitably lead to a Big Brother society. Luckily for civil libertarians, the goverment will be in charge. How, exactly?

The history of major public sector IT projects in the UK is awful. The Child Support Agency is currently in the spotlight: it has written off a couple of billion in revenue that it was never going to collect and its new computer system is months late and £50m over budget.

Now there's nothing new about IT projects going off the rails in the private sector either - and many of the most disastrous government IT projects are much bigger than projects in the private sector - but there seem to be some particular problems with the government procurement process and civil service culture that conspire to waste taxpayers' money on a grand scale.

Whether it's the abandonment of the lord chancellor's £300m system for law courts, the Individual Learning Account (scrapped after a £250m investment); the Passport Agency's 1999 attempts at computerisation that resulted in chaos; the Ministry of Defence's £300m "Pay2000" system that didn't pay anyone; the four years' delay on the national insurance system that cost £90m to fix; the Post Office benefit card (scrapped after £500m) or any of the other couple of dozen government computerisation disasters, the apparent inability of either the government or its major suppliers to make big projects work is truly upsetting.

Well, it's truly upsetting to taxpayers. To civil libertarians, though, it may be the light at the end of the tunnel. Think about what it would take to create a Big Brother-style identity card system. Cards, terminals, enrolment, replacement, access, counterfeiting, databases and so on.

It could take a decade and cost a couple of billion to build. At the end of that process, will we have a safe society, secure against crime, terrorism, dole cheats and other menaces?

It seems unlikely, if the evidence from other countries, such as France, that have ID cards, is to be believed. If the system worked at all, which is far from certain, it would be so full of flaws, bugs, errors and holes that it would not make the slightest difference to law enforcement, national security or fraud prevention. I'm not cheerful about this outcome. As a citizen, I'm keen on the goverment doing things that increase my security. From this point of view, an ID card fails on almost every count, but since it will never work anyway, so what?

What the government is likely to do instead is go down the Japanese route: every subject will get a number that will simply be added to your passport, driving licence and library card. It could also be added to your credit and debit cards, as the government is talking to banks about making them part of the new ID world as well.

So far, the Japanese experience is less than encouraging: some of the 11-digit numbers have been sent to the wrong people and the government has admitted that some (supposedly impenetrable) IT systems have been compromised. While this is far from an ideal "privacy settlement", it might be sufficient for now, because we will be able to rely on the government's inability to "join up" any of their systems to protect our privacy and the "subject number" will end up being of no more use for identifying people than NI numbers are at the moment.

Least-worst or most-best? If we have to have cards, surely it would be better to co-opt cards that people are already using for other purposes? This would tend to mean the driving licence. Despite the government's interest, private sector issuers (eg, Barclaycard) would, I'm sure, be wary of having their card used for other purposes. Apart from anything else, where would legal liability rest if someone used a card in nefarious activities?

This least-worst option may not be that bad. If every driving licence had a chip on it, then every car would pretty quickly sprout a reader so thieves couldn't steal them (your car would only work with your driving licence: if you're banned, you can't drive). Naturally, we'd want to protect civil liberties.

Hence, the driving licence would no longer have your picture, name or anything else on it. If a policeman wanted to know who you were, he'd put the card into his reader and it would disclose the relevant details.

The machine at the car park wouldn't have the relevant cryptographic keys, so it won't be able to read those details. Perhaps the best way to protect civil liberties, though, would be to privatise the system. Let any company issue the card, but make them legally liable for errors. So, if British Airways gives me a card that says I'm Dave Birch and I'm actually Osama bin Birch, the Hammer of the Infidels, they would be responsible.

Now, banks (because of existing "know your customer" legislation) would be in pole position to provide high-reliability authentication, but others (eg, the Post Office) could issue them as well. If one of these organisations abuses your privacy, then never mind the law, because you would have real recourse: you could go on Watchdog.