So here's how I off the top of my head think this will go...
No way can I see it just being a paper/card type of ID, it will probably be on your phone, much like the NHS app I have on my phone. Eventually that ID card will incoporate everything, so your drivers licence, health details, even passport one day. This will be a future dictators dream come true, no one can go anywhere unless permitted, the government will hold all the cards on your life and your compliance.
We've already seen some indications of this, with 200,000 random child benefit checks having taken place in the UK, where they accessed government border force details to check if random people had travelled abroad and how long for, without your permission or knowledge of them doing so, despite something like over 197,000+ never ever having commited any crime. And even the remaining total were mostly a misunderstanding of the rules, than actually committing a crime.
In 2026 the next lot of legislation passes where they will have access to anyones bank account details for anyone claiming state pension or benefits. They already check statements and are allowed to question transactions, but currently don't have direct access to the detail, they have to request it from the claimants and are then allowed to ask questions around any transactions that have been disclosed.
Not to forget those emergency alerts sent to people's mobiles, again something the government just went ahead and did. Covid has escalated all this to ridiculous proportions, cashless now gradually being eroded as a method of payment in many places, replaced by a digital footprint of every transcation you make, which can be accessed by the government when they feel like it, or make rules to fit.
Your phone tracks where you go, CCTV has been around now for everywhere you go, and you can't even escape it in your car ANPR. Now even facial recognition being recognised as the way forward by police forces and goverment. Let's not kid ourselves we are becoming a police state, the sort of thing often only dreamed about in North Korea and why, which of us asked for any of this, the future will not be thanking us.