Bacs overview

Bacs is the UK payment scheme behind Direct Credits and Direct Debits. Griffin supports Bacs payments so your customers can pay their bills or receive credits. To send money, use Faster Payments.

Capability	Supported
Receive Bacs Direct Credits into your accounts	✅
Direct Debits collected from your accounts by authorised organisations	✅
Send Bacs Direct Credits	❌ Use Faster Payments to send money
Collect Direct Debits from accounts at other banks	❌

How Bacs differs from Faster Payments

Faster Payments processes individual payments near-instantly, at any time of day, with real-time confirmation. Bacs is a batch scheme: payments are submitted in files, processed on a fixed three-working-day cycle, and there is no real-time confirmation of the outcome. A Bacs payment instructed today will not move money until two working days later.

Bacs payments are GBP only and can only be made between UK bank accounts.

The three-day cycle

Bacs processes payments over three consecutive working days:

Day	Name	What happens
Day 1	Input day	The sending organisation submits its payment file to the scheme. Nothing is visible on your Griffin account.
Day 2	Processing day	The scheme delivers the payment instructions to Griffin. Inbound payments and their admissions become visible over the API, but no money has moved yet.
Day 3	Entry day	Money moves. Direct Credits are credited to your account from 07:00 (UK time), and Direct Debit collections are debited from 09:00 (UK time).

Weekends and bank holidays are not working days: if the next step in the cycle falls on a non-working day, it happens on the next working day instead. See withdrawal schedules and outages for how non-working days affect payment processing generally.

Scheme limits

The Bacs scheme limits a single transaction to £20 million. For example, a single Direct Debit collection against one of your accounts cannot exceed £20 million.

Griffin does not enforce any limits in addition to the scheme's own: there is no Griffin-imposed cap on the value of a Direct Credit you can receive or a Direct Debit collection that can be taken from an account.

Bacs glossary

Bacs comes with a family of acronyms for its messaging services. Griffin and its scheme partners handle these messages for you, and our guides describe the behaviour in plain language, but you may encounter the acronyms when talking to originators or reading scheme documentation.

Term	Meaning
ADDACS	Automated Direct Debit Amendment and Cancellation Service: the messages a paying bank sends to originators when a mandate changes or is cancelled. Griffin sends these automatically.
ARUCS	Automated Return of Unapplied Credits: the mechanism for returning a Direct Credit that cannot be applied to the beneficiary's account.
ARUDD	Automated Return of Unpaid Direct Debits: the mechanism for returning a Direct Debit collection unpaid to the originator, for example when an account is closed.
AUDDIS	Automated Direct Debit Instruction Service: the service originators use to lodge, amend, and cancel Direct Debit Instructions electronically.
DDI	Direct Debit Instruction: the mandate a payer signs authorising an organisation to collect Direct Debits from their account.
DDIC	Direct Debit Indemnity Claim: the claim a paying bank raises against an originator to recover money refunded to a payer under the Direct Debit Guarantee.
SUN	Service User Number: the six-digit number that identifies an organisation collecting Direct Debits (the originator) in the Bacs scheme.