I'm British, we've also resisted it, which is why the closes thing to a national identity document I listed was a driving licence or passport. It's not uncommon

I'm British, we've also resisted it, which is why the closes thing to a national identity document I listed was a driving licence or passport. It's not uncommon to have a provisional driving licence (learners' permit to you I think) purely for the purpose of being IDd for alcohol or whatever. For tax I would use my national insurance number and any form of photo ID to register for an online account, or you can do a paper form but I don't know how they verify identity if you're claiming a refund in that case. A credit card application would similarly want a copy of photo ID and probably a proof of address (like a bank statement or utility bill). There's nothing wrong with having the number, I have a national insurance number, I have Self-Assessment Tax Return numbers (I think it's unique each year), it's the secret bit I don't get.