BACS
Bacs Payment Schemes Limited (originally Bankers' Automated Clearing Services) is a United Kingdom scheme for the electronic processing of financial transactions. BACS direct debits and BACS direct credits are made using the BACS system. BACS payments take three working days to clear: they are entered into the system on the first day, processed on the second day, and cleared on the third day.
Read more about Bacs.