Bacs (Bankers' Automated Clearing Services)

Bacs is the United Kingdom's automated clearing system for bulk, pre-scheduled payments between bank accounts. It carries two main products: Direct Debit, which lets organisations collect regular bills from customers' accounts, and Bacs Direct Credit, which lets organisations pay many people at once, most notably wages, pensions, supplier invoices and state benefits. Payments are processed in batches over three working days, which makes Bacs slower than instant systems but cheap and highly predictable for regular payments.

The name originally stood for Bankers' Automated Clearing Services; today the system is simply called Bacs. Since 2018 it has been part of Pay.UK, the operator that also runs Faster Payments and the cheque imaging system, and it is supervised by the Bank of England as well as being subject to the UK's payments regulator. It is the UK counterpart of the US ACH network, while high-value same-day payments go through CHAPS.

Think of a postal service for payroll and bills that collects letters all day, sorts them overnight and delivers them on a fixed morning. Nothing arrives instantly, but because everyone knows the timetable, an employer can be sure wages land on payday and a utility knows exactly when bills will be paid.

Bacs works like that. A company sends a file listing all the payments it wants to make or collect. Bacs sorts the instructions and passes them to the banks involved, and on the third working day money leaves one set of accounts and arrives in another. It suits regular payments planned in advance, not urgent ones.

1. Input day. The organisation, or a bureau acting for it, submits a payment file through Bacs's secure channel before the daily cut-off. Each submitter is identified by a service user number.
2. Processing day. Bacs validates the file, sorts the instructions by bank using each payee's sort code and passes them to the banks.
3. Entry day. Accounts are debited and credited, usually early in the morning, and banks settle the net amounts between themselves across their accounts at the Bank of England, a form of deferred net settlement.

Accounts are identified by sort code and account number, the domestic parts of the UK basic bank account number. If details are wrong or an account is closed, the payment is returned through Bacs's automated return and advice services, which feed into payment failure handling by the payer.

Direct Debit is a pull payment: the payer signs a mandate authorising an organisation to collect variable amounts on dates it notifies in advance. It is widely used for utilities, council tax, mortgages, insurance, gym memberships and subscriptions, and differs from a standing order, which is a fixed amount pushed by the payer's own bank. Organisations collecting Direct Debits must be sponsored by a bank and agree to scheme rules. Payers are protected by the Direct Debit Guarantee, which entitles them to an immediate refund from their bank if a payment is taken in error, a protection broader than card chargebacks for these payments. The name of the collecting organisation appears on the payer's statement in a similar way to a card billing descriptor.

Bacs began in 1968 as the Inter-Bank Computer Bureau, set up by UK banks to move routine payments electronically instead of on paper, and took the name Bankers' Automated Clearing Services in 1971. Bacs Payment Schemes Limited later became the membership company running the system, and on 1 May 2018 it became part of Pay.UK as the UK consolidated its retail payment system operators. According to Pay.UK, Bacs processed 6.86 billion payments worth £6.05 trillion in 2025, including a record 5.0 billion Direct Debits, and more than 183 billion transactions since 1968.

Bacs remains the backbone of payroll in the UK, and many households pay most of their bills through it. Its low cost per payment and settled timetable explain why it has not been displaced by faster systems for scheduled payments.

Faster Payments settles individual payments within seconds and is used for online banking transfers and many recurring payments where speed matters; CHAPS handles high-value and time-critical transfers in real time with real-time gross settlement. Bacs trades speed for efficiency and the strong mandate-based protections of Direct Debit. UK authorities have long discussed moving retail payments onto a new shared architecture, and payment initiation through open banking, including variable recurring payments, is being developed as an alternative way to collect regular payments. Elsewhere, comparable batch systems include ACH in the US and SEPA Direct Debit and SEPA Credit Transfer in the euro area under the Single Euro Payments Area.

• Pay.UK: Bacs payment system
• Bacs