Forget the politics for a moment, forget the challenges of making biometrics and a national identity register work for a little while, and please someone tell the government to employ someone who knows about selling to come up with a reason people will accept ID cards.

With today's announcement of the latest stage in the prolonged rollout of the controversial scheme, once more the biggest element lacking is a coherent and convincing reason why the cards are necessary in the first place.

ID cards will not stop terrorism - they might, in some cases, make it harder to obtain false or multiple identities, but that didn't stop the 7/7 London bombers, fully identified UK citizens all.

Voluntary passports will not work - who would suddenly decide to have a card, having happily gone through their life without one so far?

And perhaps my favourite example of daft politics is the idea that students will be the first to be offered the cards on a voluntary basis because, according to home secretary Jacqui Smith's reported comments on the BBC News web site, "they will be the most willing to accept them as they could help students do things such as open bank accounts."

Pity all those thousands of students unable to open a bank account so far. Where must they keep their student loan? Hope the boxes under their beds are secure.

Let's not forget, students are not exactly renowned for their right-wing tendencies. If one bank decides to mandate ID cards for opening a student account, it is bound to see floods of eager students queueing up - outside its rivals.

There is a case to be made for ID cards - in an increasingly connected world some form of electronic personal identity and authorisation mechanism is going to be inevitable - but the government's ham-fisted attempts to sell its proposals to a sceptical public will not get us any nearer that goal.