NIN is rarely used in the UK. You need one for student financing... and later for your employer to correctly relay your taxes to HMRC. Certainly it's not needed for banks/credit cards/phones/brokerages/etc.
The last time I opened a bank account in the UK involved me sitting in a bank employee's office with two forms of proof of identity and proof of income. I could have used my birth certificate for one but AFAIK the second would cost money.
kurtisc|7 years ago