Taken from my B/S faq's
BACS (Banks Automated Clearing System)
BACS is ideal for making regular payments into your Britannia account. A BACS transfer will take 3 Banking days to reach your account.
To complete a BACS transfer, your Bank will ask you for the information set out below.
Britannia's sort code: 57-13-27.
Account number: 00000000 (always enter 8 zeros here).
Reference: Your 9 digit Britannia account number, e.g. 123456789. If you have an 8 digit account number please add a '0' to the front of it. Your Britannia account number can be found on your passbook, cashcard or statement.
CHAPS (Clearing House Automated Payment System)
CHAPS is a same day transfer of funds. A CHAPS transfer will generally incur a cost from the transferring organisation in the region of £20. A CHAPS payment may also be refered to as a TT (Telegraphic Transfer).