Most UK savings providers ask for proof of identity and address, such as a passport or driving licence and a recent utility bill, council tax bill or bank statement. Some providers verify your details electronically, while others may also request your National Insurance number, tax-residency information or details of a linked bank account. Children’s accounts can require proof of the child’s identity and the parent or guardian’s documents. Requirements vary, so check the provider’s application page and confirm it is FCA-authorised before applying.