The sort code, which is a six-digit number, is usually formatted as three pairs of numbers, for example 12-34-56. This standard was revised in 2003 and again in 2007 when it was split into two parts. 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.