UK problems with ID cars
The most fundamental issues with the ID cards in the UK come down to two issues:
1) Becoming a non-citizen without one. So if anything happens (you lost it, or the gov screws up) then instantly you might lose the ability to do anything or get health care, etc, because now you now have to prove you are a citizen.
2) The asymmetry of the power. Basically the gov can fine to £1000 for failing to update your detail, can use or abuse the data (e.g. sell it to insurers, etc) as they want. But if they fuck up you have basically no rights to sue them in return (even if you did have that right, the asymmetry in legal resources makes that difficult).
If you look at Estonia they have a very different approach, not the database-state that our gov was wanting to create where the ID was simply to help them. In Estonia the ID card and systems have been created to provide you, the citizen and voter, with advantages.
Just note the law where you can't be pestered to provide data the gov already has, and that you have a right to see who has accessed your data.