GLOBAL PAYMENTS KNOWLEDGEISO 20022 / SWIFT / SEPA / MT / MX
PAYMENTSSIGNAL

The interactive academy for the standards, messages, and rails that move money.

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BACS (UK THREE-DAY CYCLE)

Unpaid direct debit: the ARUDD return after settlement day

Trigger: The payer's account has insufficient funds (or the Direct Debit Instruction is cancelled), so the bank cannot pay the collection.

Contributor Shubham Mathure

What operations sees first: A collection that appeared to settle on Day 3 comes back unpaid a day or two later, reported through the ARUDD cycle.

WHERE IS THE MONEY?

Not collected from Riya — the item was returned unpaid, so the money stayed in her account (or was reversed by the return).

DID SETTLEMENT HAPPEN?

The collection did not stick; the unpaid item is unwound through the ARUDD cycle after entry day.

WHO ACTS NEXT?

Bank Alfa (payer bank) Asha Traders re-presents the collection or contacts Riya; repeated unpaid items may prompt review of the Direct Debit Instruction.

PLAY THE EXCEPTION

Trigger: When Bank Alfa tries to pay the item, Riya's account has insufficient funds or her mandate has been cancelled, so the Direct Debit cannot be paid.

STEP 1 / 6INTERNAL

A mandate already exists

Riya (payer) → Asha Traders (collector/biller)

Before any money moves, Riya set up a Direct Debit Instruction (the mandate) authorising Asha Traders to pull agreed amounts from her account. The mandate is what makes a Direct Debit a PULL, and it is governed by the Direct Debit Guarantee — the payer's promise of an immediate refund from her own bank if a Direct Debit is taken in error.

Step 1 of 6: A mandate already exists

  1. 01Processing
    A mandate already existsRiya (payer) → Asha Traders (collector/biller)
  2. 02Message
    Asha Traders submits the collection fileAsha Traders (collector/biller) → Bacs (Pay.UK) · Bacs Standard 18 collection file
  3. 03Clearing obligation
    Bacs processes and passes entries to the banksBacs (Pay.UK)
  4. 04 · EXCEPTION PATHProcessing
    Bank Alfa cannot pay the Direct DebitBank Alfa (payer bank)
  5. 05 · EXCEPTION PATHMessage
    The item is returned unpaid via ARUDDBank Alfa (payer bank) → Bacs (Pay.UK) · ARUDD report
  6. 06 · EXCEPTION PATHMessage
    Asha Traders learns the collection failedBacs (Pay.UK) → Asha Traders (collector/biller)
  7. OUTCOME
    Funds
    GBP 90.00 stayed with Riya — either the debit never stuck because Bank Alfa refused to pay, or any provisional entry was reversed by the return.
    Settlement
    The collection did not complete for this item; the unpaid return unwinds it through the ARUDD cycle on days 4-5, after normal settlement day.
    Who acts next
    Bank Alfa (payer bank) — Asha Traders contacts Riya to arrange payment or re-present the Direct Debit on a future cycle if the mandate is still live.
Full step-by-step text (works without JavaScript)
  1. 01Processing
    A mandate already existsRiya (payer) → Asha Traders (collector/biller)

    Before any money moves, Riya set up a Direct Debit Instruction (the mandate) authorising Asha Traders to pull agreed amounts from her account. The mandate is what makes a Direct Debit a PULL, and it is governed by the Direct Debit Guarantee — the payer's promise of an immediate refund from her own bank if a Direct Debit is taken in error.

  2. 02Message
    Asha Traders submits the collection fileAsha Traders (collector/biller) → Bacs (Pay.UK) · Bacs Standard 18 collection file

    On day one Asha Traders sends its collection file to Bacs through its own bank, Nordbank. The file lists Riya's bill of GBP 90.00 against her mandate. This is an instruction to collect — no money has moved yet.

  3. 03Clearing obligation
    Bacs processes and passes entries to the banksBacs (Pay.UK)

    On day two Bacs validates the file and passes the entries to each bank, so Bank Alfa learns it must pay and Nordbank learns it will receive. This calculates who owes whom — obligations, not money in the account yet.

    Processing produces obligations. Bank Alfa now owes the collection and Nordbank is due it, but nothing settles until day three.

  4. 04 · EXCEPTION PATHProcessing
    Bank Alfa cannot pay the Direct DebitBank Alfa (payer bank)

    Bank Alfa finds either no available funds or a cancelled Direct Debit Instruction, so it refuses to pay this collection. The item is flagged for return rather than debited from Riya.

  5. 05 · EXCEPTION PATHMessage
    The item is returned unpaid via ARUDDBank Alfa (payer bank) → Bacs (Pay.UK) · ARUDD report

    On the days after settlement, Bank Alfa reports the unpaid item through the ARUDD cycle — the Automated Return of Unpaid Direct Debits. ARUDD is a reporting cycle that runs AFTER settlement day, so the return travels back through Bacs on day four or five, not instantly.

  6. 06 · EXCEPTION PATHMessage
    Asha Traders learns the collection failedBacs (Pay.UK) → Asha Traders (collector/biller)

    Bacs passes the ARUDD return on to Asha Traders through Nordbank. Because the report lags settlement by a day or two, the collector only learns the bill went unpaid after it looked collected — so billers wait for ARUDD before treating a Direct Debit as truly settled.

  7. OUTCOME
    Funds
    GBP 90.00 stayed with Riya — either the debit never stuck because Bank Alfa refused to pay, or any provisional entry was reversed by the return.
    Settlement
    The collection did not complete for this item; the unpaid return unwinds it through the ARUDD cycle on days 4-5, after normal settlement day.
    Who acts next
    Bank Alfa (payer bank) — Asha Traders contacts Riya to arrange payment or re-present the Direct Debit on a future cycle if the mandate is still live.

THE TIMELINE

  1. 01Asha Traders (collector)
    Submits the Bacs Direct Debit collection on Day 1 under Riya's Direct Debit Instruction.Bacs Standard 18 payment file
  2. 02Bacs (Pay.UK)
    Processes the file on Day 2 and passes entries to the banks for entry day.
  3. 03Bank Alfa (payer bank)
    On Day 3 cannot pay the Direct Debit because the account lacks funds, so the item is flagged for the ARUDD return.
  4. 04Bacs (Pay.UK)
    Reports the unpaid item to Asha Traders through the ARUDD cycle on days 4-5 — after settlement day, not instantly.

Resolution: The Automated Return of Unpaid Direct Debits (ARUDD) is a reporting cycle that runs after settlement day, so the collector learns of an unpaid collection a day or two later. The Direct Debit Guarantee also lets the payer reclaim an error immediately from their bank.

LEARN THE CONCEPTS

Sources for this scenario2
  1. Scheme-specific rule

    Bacs (Direct Debit and Direct Credit) ↗ — Pay.UK · ARUDD / Direct Debit Guarantee

    Describes Bacs, operated by Pay.UK: sterling Direct Debit (pull) and Direct Credit (push) processed on a three-working-day cycle (submission, processing, entry), with Direct Debit returns handled through the ARUDD cycle. · Checked 2026-07-14

    Bacs runs a fixed three-day cycle: day 1 submission, day 2 processing, day 3 debit and credit taken together. Direct Debit adds days 4-5 for the Automated Return of Unpaid Direct Debits (ARUDD).

  2. Simplified educational illustration

    Payments Signal editorial teaching models — Payments Signal

    This site's own simplified teaching models. · Checked 2026-07-12

    What this simplifies: Single-cycle teaching model; participant-specific handling and exact cut-offs vary.

    Used wherever diagrams, scenarios, figures, or example values are didactic constructions rather than sourced facts; every such use carries a simplifications disclosure. All people, companies, banks, and list entries in examples are fictional.