Bank Complaint to Financial Ombudsman Service 2026

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Every major bank operating in the United Kingdom — Barclays, HSBC, Lloyds, NatWest, Santander, Halifax, Nationwide, Monzo, Starling, and hundreds of others — is regulated by the Financial Conduct Authority. That means every one of them is subject to the jurisdiction of the Financial Ombudsman Service when a customer has a dispute they cannot resolve directly.

If your bank has applied unfair charges, failed to refund an unauthorised transaction, closed your account without adequate explanation, mishandled a payment, or simply provided service so poor that you have suffered a financial loss, you have a clear route to redress. The FOS is free to use, its decisions are binding on the bank, and it applies a “fair and reasonable” standard that often goes further than a court would on pure contract law.

This guide explains how to bring a bank complaint to the Financial Ombudsman Service in 2026, what types of banking dispute it covers, how to prepare your evidence, and the most common errors that cause complaints to fail unnecessarily.

When Do You Need the FOS for a Bank Complaint?

You should consider the FOS route when:

• Your bank has refused a refund for an unauthorised transaction and you believe the refusal is wrong.
• You have been charged fees you consider unfair, excessive, or applied in error.
• Your bank has closed or restricted your account without adequate notice or reason and you have suffered financial harm as a result.
• A payment you instructed the bank to make was sent to the wrong account due to a bank error, or returned funds have been delayed.
• You applied for a product — an overdraft, loan, credit card, or mortgage — and the bank mis-sold it to you or gave you incorrect information.
• You have submitted a formal complaint to the bank, received an unsatisfactory response (or no response within eight weeks), and want an independent resolution.

The FOS covers the full range of personal banking products and services, including current accounts, savings accounts, credit cards issued by banks, personal loans, overdrafts, mortgages, and payment services. It also covers small businesses meeting certain turnover thresholds.

What a Bank Complaint to the FOS Involves

A bank complaint to the FOS follows the same two-stage structure as any FOS complaint: the bank’s own complaints process first, then the FOS if the bank’s response is unsatisfactory.

The bank is required under FCA DISP rules to acknowledge your complaint promptly and issue a final response within eight weeks. For payment service complaints (such as an unauthorised transaction on a current account), a shorter 15-business-day deadline applies in most cases, though this can be extended to 35 business days in complex circumstances.

At the FOS, an investigator will review the bank’s transaction records, correspondence, and internal policies alongside your own account of events and supporting evidence. Banking disputes often turn on specific facts: exactly when a transaction occurred, what the bank’s records show about authorisation, what warnings were given, and whether the bank followed its own terms and conditions as well as applicable law. Detailed, well-organised evidence therefore makes a material difference.

One product line still generates steady FOS awards: mis-sold payment protection insurance. If PPI was added to a loan, card or mortgage you held, our PPI mis-selling claim guide covers the complaint and the undisclosed-commission angle.

Step by Step: How to Make a Bank Complaint

Step 1 — Raise the Complaint With Your Bank in Writing

Always complain in writing, even if you first called the bank. Send a letter or email to the bank’s dedicated complaints address (usually listed on its website or on the back of your bank statement). Your complaint should:

• State clearly what went wrong and on what date.
• Identify the specific transaction, charge, account, or event in dispute.
• Explain what you asked the bank to do and what it did instead.
• State the financial amount at stake.
• Specify what outcome you want: a refund, reversal of charges, correction of records, or compensation.

Keep a dated copy of everything you send. If you write by email, save the sent copy. If you send a letter, use recorded delivery or save proof of postage.

Step 2 — Wait for the Bank’s Response

The bank has eight weeks to issue a final response. For payment disputes, the bank may issue a response much sooner. Read the response carefully. If it offers you something, check whether it covers your full loss and whether accepting it involves waiving future claims.

If the bank sends a “deadlock” letter (stating it has reached its final position and the matter cannot be resolved internally), or if eight weeks pass without a final response, you may proceed to the FOS immediately.

Step 3 — Gather Your Banking Evidence

Before approaching the FOS, assemble:

• Printed or downloaded bank statements covering the relevant period.
• Copies of any payment instructions, direct debit mandates, or standing order forms.
• Records of disputed transactions including dates, amounts, merchant names, and reference numbers.
• All correspondence with the bank — letters, emails, online message centre transcripts, and any reference numbers the bank gave you.
• Notes of telephone calls: date, time, who you spoke to, what they said, and any reference number provided.
• The bank’s final response letter.
• Any evidence of consequential loss — for example, if a failed payment caused you to incur a penalty with a third party, retain the evidence of that penalty.

Step 4 — Check Relevant Rules on Unauthorised Transactions

If your dispute involves an unauthorised transaction — one you did not authorise and did not make — the Payment Services Regulations 2017 provide strong consumer protections. In most cases, a bank must refund an unauthorised payment promptly unless it can prove you authorised it, acted fraudulently, or were grossly negligent. “Gross negligence” is a high bar and not easily established merely by pointing to the fact that your device or card was used.

If you are disputing a fraudulent payment under the voluntary authorised push payment (APP) fraud code or the mandatory reimbursement scheme that came into force on 7 October 2024 (requiring banks to reimburse most APP fraud victims up to £85,000), make sure your complaint specifically references the relevant scheme and the bank’s obligations under it.

Step 5 — Submit to the FOS

Submit your complaint to the Financial Ombudsman Service within six months of the bank’s final response letter. The online form at financial-ombudsman.org.uk is the most efficient route. Provide:

• The bank’s name and the type of account or product involved.
• A chronological account of events, with dates and amounts.
• Your supporting documents, uploaded or posted.
• A clear statement of what you want the FOS to award.

Be factual and specific. Avoid general expressions of dissatisfaction. State figures precisely.

Step 6 — Engage With the Investigation

The FOS investigator will contact both you and the bank. The bank will be asked to provide its full complaint file, transaction data, and internal communications. You may be asked to clarify aspects of your account or provide further documents.

Respond promptly and concisely. If the investigator’s provisional view goes against you, you have the right to make further representations before a formal ombudsman decision is issued.

Step 7 — Accept or Challenge the Outcome

If the ombudsman’s final decision is in your favour, you have a set period (typically 28 days) to accept. On acceptance, the bank is legally bound to comply. If the decision goes against you, you may still pursue the matter in court — though the FOS decision will likely be considered.

Key Deadlines

What Happens After You Submit

The FOS may take three to six months to resolve a straightforward banking complaint. Complaints involving fraud, complex transactions, or systemic issues may take longer. The current maximum FOS award is £455,000 per complaint for events from 1 April 2019.

Common outcomes in successful bank complaints include: a full or partial refund of unauthorised transactions, reversal of unfair charges with interest, compensation for consequential financial loss, compensation for distress and inconvenience, and a correction to your credit record where the bank’s error has caused a negative entry.

Common Mistakes

1. Failing to complain in writing to the bank first. A phone call is not sufficient proof that you complained. Always follow up in writing and keep a dated copy.
2. Accepting the bank’s first offer without considering the full loss. Banks sometimes offer a partial goodwill payment that does not cover the full extent of your loss, including interest and consequential harm. Calculate your total loss before accepting anything.
3. Missing the six-month deadline after the final response letter. Banks are required to tell you about the FOS in their final response. Note the deadline and act on it.
4. Claiming gross negligence is the same as ordinary negligence. If the bank claims you were grossly negligent (for example, in an unauthorised transaction dispute), it must demonstrate conduct that is highly unreasonable, not merely careless. Do not concede this without challenge.
5. Not quantifying consequential loss. If the bank’s error caused you to miss a payment to a third party, incur a penalty, or lose an opportunity, document that loss specifically. The FOS can award it.
6. Describing the dispute without transaction-level detail. Investigators need account numbers, transaction dates, amounts, and merchant references. A general account of events without this detail delays resolution.
7. Assuming the FCA will sort it out. The FCA regulates firms collectively and does not resolve individual disputes. The FOS is the correct route for personal redress.

The Rules That Apply

Banking complaints to the FOS are governed primarily by:

• The Financial Services and Markets Act 2000 (jurisdiction and binding decisions).
• The FCA Handbook, DISP — Dispute Resolution: Complaints (bank obligations to handle complaints).
• The Payment Services Regulations 2017 (unauthorised transaction protections and payment error liability).
• The Payment Systems Regulator’s mandatory APP fraud reimbursement rules (7 October 2024 onwards, for authorised push payment fraud).
• The Consumer Duty (FCA, July 2023 onwards) — requiring firms to act to deliver good outcomes for retail customers.

The FOS applies these rules alongside a “fair and reasonable” standard that looks at what good practice in banking requires, not only what is technically permitted under the contract.

Related Court Forms & Guides

• Form N260: Statement of Costs — the costs schedule used at summary assessment.
• Form N244: Application Notice — the form for interim applications.
• Start a Money Claim Online (OCMC) — where most civil money claims begin.
• Particulars of Claim — setting out the basis of your claim.
• Civil Court Forms Index — every civil court form guide in one place.

How Chris Can Help

A bank dispute involving unauthorised transactions, account restrictions, or complex charges can involve a great deal of evidence and careful legal framing. Chris can help you draft a precise complaint letter to your bank, organise your transaction evidence, identify the specific regulatory provisions that apply, and prepare a clear FOS submission — all without solicitor costs.

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Frequently asked questions

When can I take a bank complaint to the FOS?

You must complain to your bank in writing first. If the bank issues an unsatisfactory final response or a “deadlock” letter, or does not give a final response within the time allowed, you can then take the complaint to the Financial Ombudsman Service for an independent decision that is binding on the bank.

What kinds of banking disputes does the FOS cover?

The FOS covers the full range of personal banking products and services — current and savings accounts, credit cards issued by banks, personal loans, overdrafts, mortgages and payment services — including unfair charges, unauthorised transactions, unfair account closures, payment errors and mis-selling. It also covers small businesses, charities and certain trusts that meet the eligibility thresholds.

The bank says I authorised a transaction I dispute. Who has to prove it?

Under the Payment Services Regulations 2017 the burden of proof is on the bank: it must show that you authorised the payment, acted fraudulently, or were grossly negligent — and “gross negligence” is a high bar. Keep all evidence that you did not make or authorise the payment and submit it to the FOS, which will review the bank’s authentication records alongside your account.

My bank refused to refund APP fraud. What are my rights?

For authorised push payment (APP) fraud, mandatory reimbursement rules require most banks to refund victims in most cases, unless the customer was grossly negligent or acted fraudulently. If your bank has refused, make sure your complaint references the relevant scheme, and the FOS can review whether the refusal was correct. Check the current reimbursement limit and rules for your situation.

What evidence should I gather before going to the FOS?

Assemble bank statements for the relevant period, records of the disputed transactions (dates, amounts, merchant names and reference numbers), all correspondence with the bank, notes of phone calls, the bank’s final response letter, and any evidence of consequential loss. Transaction-level detail makes a material difference — a general account of events without it delays resolution.

Is there a deadline to bring my complaint to the FOS?

Yes. There is a set period to contact the FOS after the bank’s final response, and separate time limits running from the underlying events. The bank must tell you about the FOS in its final response — note the deadline and act on it. Always check the current time limits that apply to your situation.

Related guides: Particulars of Claim · Start a Money Claim Online (OCMC) · Form N244: Application Notice · All civil court forms