How to Complain to the Financial Ombudsman — Step by Step
Complete guide to making a complaint to the Financial Ombudsman Service (FOS) in the UK. Covers when to complain, how the process works, timelines, and what outcomes to expect.
·5 min read
If you have a dispute with a bank, insurer, or financial firm and they will not resolve it, the Financial Ombudsman Service (FOS) can investigate and make a binding decision. Here is how the process works.
When to Use the Financial Ombudsman
Use the FOS for complaints about
Do NOT use the FOS for
Banks and building societies
HMRC (use tax tribunal)
Credit card and loan companies
DWP / benefit decisions (use mandatory reconsideration, then tribunal)
Insurance companies
Accountants (unless FCA-regulated)
Mortgage lenders and brokers
Employers (use employment tribunal)
Financial advisers (FCA-regulated)
Solicitors (use Legal Ombudsman)
Investment and pension firms
Energy companies (use Energy Ombudsman)
Money transfer services
Telecoms (use Ofcom/CISAS)
Debt collectors
NHS (use Parliamentary and Health Service Ombudsman)
Payday lenders
Unregulated cryptocurrency firms
Step-by-Step Complaint Process
Step 1: Complain to the Financial Business First
Detail
Information
This is required
You MUST complain to the firm first — the FOS will not investigate until you have
How to complain
In writing (email or letter) — keep a copy
What to include
What happened, what went wrong, what you want them to do about it
Their deadline
They must give a final response within 8 weeks
If they do not respond in 8 weeks
You can go straight to the FOS
If they refuse your complaint
You receive a “final response letter” — you can then complain to the FOS
Step 2: Receive the Final Response Letter
Outcome
Your next step
Firm upholds your complaint and offers fair resolution
Accept — complaint resolved
Firm offers a partial resolution
Consider whether to accept or escalate to FOS
Firm rejects your complaint
You have 6 months to refer to the FOS
No response within 8 weeks
Refer to the FOS immediately
Step 3: Submit Your Complaint to the FOS
Method
Details
Online
financial-ombudsman.org.uk — quickest method
Phone
0800 023 4567 (free), 0300 123 9123
Post
Financial Ombudsman Service, Exchange Tower, London E14 9SR
What to include
Your details, the firm’s details, what happened, what you want, copies of key correspondence
Time limit
Within 6 months of the firm’s final response letter
Step 4: FOS Investigation
Stage
What happens
Acknowledgement
FOS confirms receipt and assigns your case
Information gathering
FOS requests documents from you and the firm
Assessment by caseworker
An adjudicator reviews the evidence and gives an initial opinion
Initial opinion
If you accept — case resolved. If not — request an Ombudsman’s decision
Ombudsman’s decision
A senior Ombudsman reviews the case and makes a final, binding decision
When you spoke to the firm, who you spoke to, what was said
Be specific about what happened
Facts and chronology matter more than emotion
State what you want
Be clear about the outcome you are seeking
Explain the impact
How were you affected financially or emotionally?
Respond promptly to FOS requests
Delays on your side slow the process
Be honest
Inaccuracies undermine your credibility
Include a timeline
Especially helpful for complex complaints
What to Include in Your FOS Complaint
Essential information
Details
Your full name, address, date of birth
For identification
The firm’s name
Who you are complaining about
Account or policy number
Helps the firm locate your records
Timeline of events
What happened and when
How the firm responded to your complaint
Include their final response letter
Evidence supporting your complaint
Correspondence, statements, screenshots
What you want
Refund, compensation, correction to your account, etc.
The impact on you
Financial loss, stress, inconvenience
Timeline
Stage
Typical duration
Complain to firm
Allow 8 weeks for their response
Refer to FOS
Must be within 6 months of final response
FOS acknowledgement
1–2 weeks
FOS investigation
3–12 months (varies widely)
Adjudicator’s opinion
Part of investigation
Ombudsman’s final decision (if requested)
Additional 3–6 months
Payment of compensation (if awarded)
Within 28 days of accepting the decision
If You Disagree with the FOS Decision
Option
Details
Accept the adjudicator’s opinion
Case resolved — firm must comply
Reject and request Ombudsman’s decision
A senior Ombudsman reviews from scratch
Accept the Ombudsman’s decision
Legally binding on the firm — you receive what was awarded
Reject the Ombudsman’s decision
Decision does not bind you — you can pursue other options (e.g. court)
Take legal action instead
You can sue the firm in court, but cannot usually do both
The Ombudsman’s decision is final for the financial firm — they cannot appeal. If you accept it, they must pay. If you reject it, you keep your right to go to court but the FOS decision carries weight.