I would say that what is needed is a functioning system, a card per se is not a prerequisite for the system to work, as foreign countries have demonstrated. There you can (in most countries) get a card for the purpose of proving your identity if you feel you need to (carrying a card is a requirement in some countries, but not all) so long as the system works (like abroad), a card is mostly for things other than proof of duties and entitlement because they are fixed according to your residence status. Elsewhere, so long as you are entitled to residency, you decide whether you want to take it up or not (i.e. live, pay and claim). If you are already a national then the system has that established from the point of you becoming a national (birth or on successful application) - you cannot become a national and/or take part in society (live, pay and claim) unless you either are/become a national or otherwise legitimately claim residence, and are registered as such. If you are not registered you cannot claim any rights and you won't be asked to pay - in a proper system. Incidentally, in a proper system nationals can register as non-residents and thereby renounce rights to claim and thereby step outside the payment system (taxation). Property owning, etc. non-nationals can also register as non-residents. If either nationals or non-nationals registered as non-residents infringe taxation rules regarding economic activity within the country or length of stay limitations, a proper system will treat them as residents but then along with payment and other duties they automatically get a resident's rights regarding claims. This is all very foreign and un-British.