Formal complaint letter: prepare and post your UK complaint
Write a formal complaint to a UK business about goods, services or billing. Get an English example, evidence checklist and guidance on replies and posting.
Quick answer
A formal complaint letter sets out what went wrong with goods, a service or a bill, and what you want the business to do. Follow the business’s complaints procedure, include your reference, key dates, evidence and the remedy you want, and ask for an acknowledgement and complaint reference. If the complaint is not resolved, the next step may be an ombudsman or ADR scheme, depending on the sector.
| Who it’s for | Customers of a UK business with faulty goods, poor service or a disputed bill |
| What to include | Reference, dates, what happened, previous contact, remedy requested, evidence copies |
| Reply time | Suggest a reasonable date; the sector or published procedure may set its own timescale |
| Escalation | Next stage of the complaints procedure, then an ombudsman or ADR scheme where eligible |
| How to send | By the route the procedure accepts: letter, email or online form; keep copies |
| Common mistakes | No clear remedy, missing references, sending original documents, confusing it with a letter before action |
A formal complaint records what went wrong and what you want the business to do. Use it for faulty goods, disappointing service or a disputed bill, especially when earlier contact has not resolved the problem. This guide provides general writing guidance for complaints to UK businesses; rights and escalation routes depend on the sector and UK nation. Follow the business’s complaints procedure, which may also accept email or an online form.
Prepare the facts and your request
- Check the complaints team’s current address and your order or account reference.
- Set out the key dates, what happened and any previous attempts to resolve it.
- Explain the effect on you and the outcome you request: a repair, refund, bill correction or explanation, as appropriate. State any amount and how you calculated it.
- Enclose copies of relevant receipts, correspondence or photographs; keep the originals.
- Give your contact details, request acknowledgement and a complaint reference, and suggest a reasonable reply date.
Formal complaint letter example
Replace every placeholder and describe only what happened in your case. Choose the remedy that fits the problem; the example does not establish an entitlement to compensation.
[Your name and postal address]
[Business name and complaints address]
[Date] — [Customer or order reference]
Formal complaint — [brief description of the issue]
Dear Complaints Team,
I am writing about [product, service or bill]. On [date], [explain what happened and how it affected you].
I previously contacted you on [dates and references]. The problem remains unresolved because [reason].
To resolve this complaint, I ask you to [requested action]. [If relevant, state the amount requested and explain the calculation.] I enclose copies of [supporting documents].
Please acknowledge this letter, provide a complaint reference and let me know your response by [reasonable requested date]. If your published procedure requires a different timescale, please explain it and tell me when I can expect an answer.
Please reply using [postal address or preferred contact details].
Yours faithfully,
[Your name]
After you complain
Keep your letter, attachments and replies. Reply and escalation deadlines vary by sector; a date you request does not replace the applicable rules. If the response does not resolve the issue, follow the next stage of the business’s procedure and check the relevant ombudsman or alternative dispute resolution (ADR) scheme’s eligibility and referral deadlines. The Financial Ombudsman Service considers eligible financial complaints; other sectors have different routes. If you later consider court action in England and Wales, check the letter before action guide and the applicable pre-action requirements: an ordinary complaint does not automatically fulfil them.
Post your completed letter
Keep a copy of the letter and attachments. Proof of posting, tracking and a delivery signature record different things; none alone establishes the contents or guarantees valid legal service. Before paying, check whether the available mailing service provides the evidence and timing your case needs. Upload your completed PDF or write your letter in MaisonMail. Enter the recipient’s full address: it determines the destination. Available services, estimated delivery and the final price appear before payment.
Official sources
References used and links to the rules currently in force.
- Complaining about the poor standard of a service – EnglandCitizens Advice
- How to complain about a financial businessFinancial Ombudsman Service
Information current as of the last verification date. This guide is informational and is not legal advice — for a complex situation, consult a qualified professional.
Frequently asked questions
What should a formal complaint letter include?
Your contact details and customer or order reference, the key dates and what happened, previous attempts to resolve it, the effect on you and the outcome you want, any amount and how you calculated it, and copies of relevant receipts, correspondence or photographs.
How long should I give a business to reply?
Suggest a reasonable reply date, but reply and escalation deadlines vary by sector and by the business’s published complaints procedure. A date you request does not replace the applicable rules.
What can I do if the business does not resolve my complaint?
Follow the next stage of the business’s complaints procedure, then check whether an ombudsman or alternative dispute resolution (ADR) scheme covers the sector, including its eligibility rules and referral deadlines. The Financial Ombudsman Service considers eligible financial complaints.
Is a complaint letter the same as a letter before action?
No. An ordinary complaint does not automatically fulfil the pre-action requirements for a court claim in England and Wales. If you later consider court action, prepare a separate letter before action.
Related guides
- Letter before action: prepare and post your letterPrepare a letter before claim for England and Wales: what to include, reply deadlines and how to post your completed letter online.
- Cancellation letter: cancel a UK service or subscriptionPrepare a UK cancellation letter: check the contract, cooling-off eligibility, notice period and fees, then adapt an English example and post it online.
- HMRC / DWP letters: prepare and post your correspondencePrepare HMRC service complaints and DWP mandatory reconsideration letters: English examples, correct office, references, deadlines and online posting.
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