This looks like an IBAN (International Bank Account Number): GB 29 NWBK 601613 31926819 Country code United Kingdom Check digits ✓ IBAN mod-97 Bank identifier Branch identifier Account number Links Wikipedia: International Bank Account Number — en.wikipedia.org Sources ISO 13616-1:2020 — Financial services — International bank account number (IBAN) — Part 1: Structure of the IBAN — iso.org IBAN Registry — swift.com