> What really is the Government going to do with a digital ID service that they can't do already?

In 20 years, the UK suffers a terrorist attack just before an election, and then elects a ultra right wing government on a platform of "remigrating foreigners." You're a British born citizen but your mom fled from Iran in the 80s and immigrated to the UK.

If you don't have digital ID, and the government decides to "remigrate all Iranians," they have to collect information from several different government groups, e.g. maybe your mom got a passport in which case one government agency may just know she's a non-native British citizen but nothing more. Maybe your immigration agency stands up to the government and engages in legal battles to prevent turning over immigration information.

However if there's a digital ID system that lets the government instantly know everything about a person, you lose the protection of friction.

I believe this is one of the fundamental premises of representative liberal democracy, and one of its most redeeming features: balance of power is spread not just between branches of government, but through ministries/departments/agencies, which makes it much harder for a despot to do despotism.