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. Every company that does financial transactions can benefit from having a SORT Codes database to verify it's payments, minimizing the risk of mistyped or incorrect data.
IBAN and BIC codes are widely used means of identifying bank account numbers, but not the only international system.
UK clearings systems:
UK Clearing systems
BACS: Bulk electronic clearing
CHAPS Sterling: High value, same day sterling payment clearing
CHAPS Euro: High value, same day euro payment clearing
Cheque and Credit Clearing: Cheque clearing for Great Britain & Northern Ireland.
In particular cases where 00 is a valid check digit, 97 will not be a valid check digit, likewise if 01 is a valid check digit, 98 will not be a valid check digit, similarly with 02 and 99.