It looks like this idea is intended to enable the police to identify “illegal” UK residents. That sounds OK, but what really happens when “illegals” are found? The vast majority certainly won't be deported.
All that is needed is a girlfriend/boyfriend/child or pet dog and they can claim that deportation would infringe their human right to a family life. They would then be given indefinite right to stay, a smart new ID card and passport plus advice on how to claim benefits.