They could have rolled out ID cards by making learners driving permits a 10 year permanent form of ID adding the biometric gubbins on there. I wonder how much that would have cost? Or maybe have a passport card for your wallet to go with the traditional form factor for travelling outside Europe, to be included in the current price.
I'm sure neither of these would have cost £4.5+ Billion and then most people would have been automatically carrier of the ID card quickly, or certainly within the 10 year period in which their existing ID will expire.
As for an entitlement card what happens if you're mugged and it lands you in the hospital, are you not entitled to treatment? If you're stopped on the street without your wallet are you not entitled to avoid prison? Would you have needed it when catching a bus?
Having an ID scheme in Russia didn't stop terrorism, so why will it work here?