The I.D. cards the Government want us all to have contain biometric information, namely a fingerprint. The only people who can access that information would be a Government department, such as the Police. I.D. cards may have their uses, such as proving your age getting into pubs or buying booze for the gang of goths round the corner, but are actually sod all use for anything else.
If I had a twin, even if he wasn't identical, he could probably get away with using it, unless he was fingerprinted.
I have a storage unit which is very secure as I have to scan my thumbprint to get into the building. The problem is, the machine doesn't recognise my print. I have to get a bloke to use his to open the lift for me.
Some of the airlock type doors at the Airport use a retinal scan. Mine aren't recognised by the scanner. I have to get a security bloke to open the doors for me.
Maybe all this technology isn't a great as it's supposed to be.