Birmingham Midshires Sort Code

Building societies have historically operated 'off the grid' when it comes to the UK clearing system, issuing their own internal 'roll numbers' and account numbers for operating their members' accounts.

So, if you wanted to transfer money to a building society account you would pay in to the building society's collection account at a bank (using a sort code), using your own account/roll/reference details as a reference.

The building societies, unlike banks, didn't have a separate sort code for each of their branches and essentially piggy-backed off a mainstream bank's clearing system.

These days some BSs have their 'own' sort codes (although not for every branch - I think Nationwide which I use has about 10, but they are tied to the product type and not to an individual branch). On my Nationwide example my current account has it's own sort code and account number combo which is sufficient to identify the account directly, while my savings accounts use a different standard sort code and a general account number and I need to quote my own specific roll/reference code xxxxx/xxxxxxxxx to actually reach my account.

Where building societies use sort codes to clear money you might expect that if they were part of a big corporate group you would expect that the sort codes would be associated with one of the banks in that group e.g. HBOS. However, BM have only been part of HBOS for a decade and a half; prior to that they only existed in the building society world. So, just because they merge or get taken over they will not necessarily rip out the legacy clearing system and start again. Looks like BM are continuing to use Barclays to provide clearing. Likely a legacy arrangment that's not worth replacing as they have longstanding agreements.

As you can see from BM savings http://www.bmsavings.co.uk/existing-savers/managing-your-account/managing-your-postal-account/, all savings account use one sort code and account code on the banking system, plus their own reference.

If you want to pay a lump sum off your BM mortgage by CHAPS you send the money to BM's account at Barclays Wolverhampton which has that same sort code and account number. http://www.bmmortgages.co.uk/important-information/questions/

So basically Barclays host an account for BM to provide clearing, and BM have not felt the need to change the longstanding arrangement just because they are now owned by a rival of Barclays.