I hope the card will include an asymmetric digital signature from a government authority. That way, concerned members of the public will be able to verify anyone else’s Brit Card.
This would in turn enable citizen-operated checkpoints to verify the Britishness of food delivery drivers, mosque worshipers, suspected pedos, anyone who smells a bit too much like curry or garlic, or blokes what look funny like they aint from round ere.
Marvellous! /s