As someone else said, it's mostly a figleaf because in practice the government does everything an ID requires, just in roundabout ways. For tax stuff everyone h

As someone else said, it's mostly a figleaf because in practice the government does everything an ID requires, just in roundabout ways. For tax stuff everyone has a National Insurance number (I think assigned at birth?) so in a sense everyone already does have a unique identifier but you can't use a National Insurance card as ID because it doesn't have a photo. Instead you just have to present a random selection of documents like a driving licence, utility bill, letter from the council etc whenever you want to open an account somewhere. I personally don't have any problem with national ID for the reasons you state.