The practicalities of the scheme will be subject to a consultation, which will also look at how to make it work for those without a smartphone or passport.
I suspect this means that it will be digital first. But with a card/passport based option available.
Previous schemes have always fallen through in the UK as they’re surprisingly unpopular. Linking it to the current debate around immigration might make it easier. But it’s still a tough sell and will get bogged down by political in-fighting and bureaucracy.