It's been a while, but once again I'll try to write a defense of ID cards, this time taking a look the way government agencies look after their data and what advantages an ID card scheme could bring. I do realise that I've not yet touched on Civil Liberties issues, I'll be addressing that issue next.
As it stands, the database state is not omnipotent, it's actually a bit thick. Different departments know different facts about you, but there is no easy way to tie these various bits and pieces together. Further to this, there is no easy way for a state agency to check that the information it's been given is correct. Identity documents might work here, but there are often easily forged and very few act as concrete proof of address, there are also similar problems with the actual issue of these documents in the first place. Time for background checks are often tight, especially when the request is for something of a high volume nature.
The check that is performed for the ID card combines an interview with a background check and a check against existing biometrics for duplicates. It's not perfect, but it's a stronger and better check than anything else. At this point the system would assign a unique reference number in order to unqiuely identify that person. Once a record is present on the national identity register it means that a check can be performed with a similar level of strength in a matter of seconds using a card fingerprint combo.
The advantage this gives to government agencies is twofold, first whenever you have to confirm your identity, the process will be faster and harder to fool. It'll no longer be able to give a false address, or impersonate someone else. This will mean that any future government IT project (carbon credits for example) will be able to use an out of the box customer identification system with built in checks to assist in identifying and preventing fraud.
The second is that it will be far easier to cross check data against that held by other agencies. As an example of the benefits of this kind of cross checking, the audit commissions data matching progamme identified £140 million in benefit fraud and overpayments. Rolling out this kind of checking across government departments could lead to considerable savings by pre emptively identifying problems such as overpayments.
Overall, rather than being viewed as an expensive white elephant, there is a good chance that an ID card system will, in the long term lead to cost savings.