Look back to 2005, and plans for an ID card were a lot more modest. The £3bn estimated cost was blown out of the water by a report from the LSE, putting the final figure closer to £10bn. Don't forget to look through suppressed documents made available under the Freedom of Information Act that suggest multiple reasons for the scheme.
There are various reasons why a national ID card won't do what the government thinks it will do. At present, we rely on multiple forms of ID, which create a patchwork of different points of contact with officialdom, both commercial and governmental. This appears to work quite well. Single ID cards, as used by Spain, for example, don't. Every one of the bombers who attacked Madrid had a valid national ID.
Identity Fraud isn't necessarily a case in point, either. LSE estimates that, rather than preventing £1.3bn of fraud a year, an ID card will hit, at most, £35m.
Finally, it won't be compulsory to carry a card. One wonders if a nation that has alread sleepwalked into a surveillance society will refuse cards if they provide notional convenience, but the signs are that the public is becoming increasingly worried about these things. Let's hope that the spirit of Clarence Willcock lives on. In the mean time, expect more spending, more consultants, and the ID Card scheme to spread further and further afield.