A sort code is a number which represents a bank branch and intended for internal processing. It identifies both the bank and the branch where the account is held. Clearing requirements
All bank offices participating in any of the following clearings must have a sorting code:
Every bank office with a sorting code does not necessarily participate in all these clearings, however, once a sorting code has been issued to a bank office, the same sorting code will be used in all of the clearings. The current standard is ISO 13616:2007, which indicates SWIFT as the formal registrar.
Before IBAN, users, especially individuals and small businesses (SMEs), used to be confused by the differing national standards for bank account identification such as bank, branch, routing codes and account number.