Behind every sort code is an allocation, and behind the allocation is a question of how an institution reaches the payment system at all. Some hold their own settlement account and clear directly. Others reach the system through a sponsor. Both end up with sort codes, and understanding the difference explains a good deal about which codes exist and why the population of them has changed so much.
Direct participation and sponsored access
An institution can participate in a UK payment system directly, which means holding a settlement account and clearing in its own name, or indirectly through an agency arrangement with a participant that clears on its behalf. Both routes result in customers holding a sort code and account number that look identical from the outside. The difference is invisible in the digits, which is one reason the code alone cannot tell you very much about the institution behind it.
Why newer firms appear in later ranges
Ranges are allocated as they are needed, so institutions that joined the system more recently hold codes from ranges allocated more recently. That produces a rough chronology across the whole code space, which is interesting and not something to rely on: ranges are reassigned, institutions merge, and a code that was allocated decades ago may be in use by a firm that did not exist then. It is a tendency, not a rule you can read a number against.
What follows for checking a code
Because neither participation route nor allocation history is readable from the digits, checking a sort code means checking it against a source outside the number. That is either the licensed register, which this index does not republish, or the institution's own published statement about its identifiers, which is what this index collects. For a payment, the check that actually protects you is neither of those: it is the name check that runs when you add a payee.
A short routine before sending
Confirm the institution from the payee rather than from a search. Read the sort code, account number and account name from a source the payee controls. Add the payee in your banking app and read the name check result properly rather than clicking through it. Telephone on an old number if anything has changed. Send a small first payment to a new relationship. None of that requires a directory, and all of it is stronger than one.
Questions people ask about sort code 040075
Does a sort code tell me if a bank clears directly?
No. Direct participation and sponsored access produce sort codes that look identical from the outside.
Do newer banks have higher sort codes?
As a tendency, because ranges are allocated as needed. It is not a rule, because ranges are reassigned and codes outlive the firms they were issued to.
Can I tell anything about the bank from 040075?
Only that it sits in a range allocated to an institution. The mapping from range to name is the licensed register, which this index does not republish.
What check should I run before paying?
The name check that runs when you add the payee in your own banking app, plus a telephone confirmation if the details are new or changed.