Incidentally, this is the data which will be processed:
user’s full name;
date of birth;
home address;
email address;
photographic images;
various identifiers such as passport number or driving licence number;
attributes held by government departments necessary for verifying the identity of an individual;
the outcome of identity checks previously performed on a user; and
transactional data, for example, income
It goes much further than ID cards in many European countries.
Government Gateway already holds much of the data, but doesn't have photographic ID, passport or driving licence ID.
Law enforcement authorities can access all this, if they need to, but why does HMRC need a photo to calculate tax or why does a buss pass holder need to declare income?
I'm not against ID cards, but this is going too far.