Are you talking about what will be stored on the phone? That's basically a distraction.
The point is to create a single ID for each person to support a unified super-database. All the chat about smartphones is to make people think that they are in control of the data and how it will be used.
If you are right and that is the point, it isn't described anywhere in the proposal which has been developed over several years. Far from from a "Unified super-database", the government's role is only as reference through an API in front of departmental databases. There's no current proposal to merge them, or assume the role of the verification services who are all third party.
Then, there's no single digital identity. The wallet will hold any number of 'digital identities', each tailored to specific purposes. Each of these identities is a bundle of a subset of the attributes/proofs saved in the app. These identities can be generated on the fly in response to a prompt, but seemingly can be manually created too.
A couple of examples. For a financial application, you might need to show the financial service you're applying to a comprehensive set of data. But to get into a nightclub, you will only need a single Zero-Knowledge Proof confirming you are over 18. These will be two separate IDs. Can you see how this might strengthen citizens by giving them control over what data they show?
Beyond that, there are principles of Purpose Limitation and Minimisation which prevent potential abuse, such as companies demanding information they legally don't need.
You appear to be are under a serious misapprehension about the proposal.
> The new digital ID will be the authoritative proof of who someone is
Obviously this will not just be stored on your phone. There will be a backend database of all issued IDs. Which will then serve as an authoritative identity system for unifying government databases.
Restrictions on how companies can use this are nice. I'm more concerned about what the government will do with it.
> Obviously this will not just be stored on your phone. There will be a backend database of all issued IDs. Which will then serve as an authoritative identity system for unifying government databases.
Incorrect, that isn't the proposed system at all. In fact, Government is kept out of the loop, except as a reference. You seem not to understand what the IDs are, so I'll try again to explain their form.
The wallet (the app) holds data that you enter. A datum might be your name or national insurance number, citizenship etc. These are verified individually by the verification service and it returns each one with a cryptographic signature. The 'ID' is then a container for proofs. It exists only on your phone. It's totally disposable. Delete a container and you can regenerate it. And you'll have more than one, many more in fact, for all different uses. Each will have a different selection of attributes and their signatures. The IDs never exist anywhere else other than on your phone. There's no database of IDs, and the app has no contact itself with the government API. Representing it in any other way is a fundamental misunderstanding of the proposal. The proposed format simply doesn't work the way you claim.
The point is to create a single ID for each person to support a unified super-database. All the chat about smartphones is to make people think that they are in control of the data and how it will be used.