For reasons I’ve never really understood the UK (or at least the UK parliament) is wildly opposed to ID cards. There’s been a few attempts to introduce them which got massive pushback and were eventually aborted.

Personally I think it would be quite a bit easier than the current mish-mash of identification documents for different purposes, everyone in practice carries some form of ID if only so they can show it when buying age restricted products on the odd occasion someone asks for verification.