How to complain about a bank, energy supplier or water company in the UK — and get compensation

In Britain a complaint is not an emotion, it is a procedure on a clock. The company has a fixed window to reply, and if it misses that window or fobs you off, an ombudsman takes the case for free — an independent body whose decision binds the company once you accept it. No court, no lawyer, no fee.

Newcomers often do not know the system exists, which is exactly why wrong bills, double charges and "there's nothing we can do" drag on for months. Here is who covers what, the deadlines, and what to write.

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How does a UK complaint actually work?

Three steps, always the same.

One. Complain to the company itself. Not a support chat — a formal complaint, by letter or through the complaint form on its website. The clock starts here.

Two. The company investigates and sends a final response. The rules require it to tell you what to do if you disagree and which body to go to. If it believes it can do no more, it issues a deadlock letter. That is not a rejection — it is your ticket to the next step.

Three. The ombudsman or sector regulator. Free. It looks at the substance rather than the paperwork, and can order money back, records corrected, and something on top for the trouble.

The key thing to remember: you can go to step three without a reply at all — simply once the deadline has passed. Silence works in your favour.

Bank, card, loan, insurance — who handles it?

The Financial Ombudsman Service (FOS). It covers banks, building societies, credit cards, loans, insurance, pensions and investments.

Complain to the firm first. It has up to 8 weeks to give a final response; payment services are quicker. After the final response you have 6 months to bring the case to FOS. Miss it and the case will most likely not be taken — the most common own goal in the whole process.

The service is free. FOS says so plainly: you do not need to pay a lawyer or a claims management company, you can fill in the form yourself, and a friend or relative may help.

How much FOS can award: for cases referred on or after 1 April 2026 about acts on or after 1 April 2019, the limit is £455,000. That is the ceiling on a binding award; above it, the ombudsman can only recommend.

Interest is separate. From 1 January 2026 FOS calculates it using a time-weighted average of the Bank of England base rate plus one percentage point (previously 8% simple a year). If the firm pays late — usually beyond 28 calendar days from your acceptance — 8% simple a year applies on top.

Gas and electricity: what if the bill is wrong?

Same shape, different body: the Energy Ombudsman.

The supplier gets 8 weeks. You can go earlier only with a deadlock letter, and from the date of that letter you have 12 months to act.

The service is free and a decision normally arrives within 6 weeks, longer for complex cases. A typical financial award is £50–100 — this is not a windfall but an acknowledgement, plus the bill correction, which is usually where the real money is.

Water: what are the deadlines here?

Three stages rather than two, and tighter on time.

Stage 1. Complain to the water company. It must reply within 10 working days. If it does not, you may qualify for a payment under the Guaranteed Standards Scheme.

Stage 2. Ask for a second-stage review. Another 10 working days.

Stage 3. CCW, the Consumer Council for Water — free and independent. You can go there once you hold a final response or once 8 weeks have passed. CCW replies within two working days and assigns a named adviser. Phone 0300 034 2222 for England, 0300 034 3333 for Wales.

Broadband, mobile and landline — how long is the wait?

Shorter: the provider gets 6 weeks, not eight. After that it goes to the sector's alternative dispute resolution scheme; for most providers that is the Communications Ombudsman.

With a deadlock letter you can go immediately, and you then have 12 months. The service is free and a typical award is the same £50–100 plus an order to put things right. The scheme is explicit that its job is to resolve disputes, not to punish providers.

What if the problem is a purchase rather than a company?

Two different mechanisms apply, and they are routinely confused.

Section 75 of the Consumer Credit Act: if you paid by credit card and the cash price is more than £100 and not more than £30,000, the card issuer is equally liable with the seller. The shop vanished, the tour never happened, the furniture never arrived — you can claim against the bank. That is law, not goodwill.

Chargeback is something else: a rule of the Visa, Mastercard and American Express schemes rather than a legal right. It works with debit cards too, and the window is around 120 days depending on the circumstances. The bank is not obliged, but usually helps where the grounds are reasonable.

The practical lesson: pay for big purchases — holidays, appliances, building work, furniture — by credit card even when you have the cash. £100 is the floor below which Section 75 does not apply at all.

What should the complaint letter say?

A British complaint is a short document in five blocks. Anger and demands for punishment work against you.

1. Who you are: name, account or contract number, address.
2. What happened: dates, amounts, reference numbers — facts, no adjectives.
3. Evidence: a list of attachments — statements, screenshots, letters, call references.
4. What you want: specifically. "Refund £142.60, correct the March bill, remove the marker from my credit file." Not "take action".
5. The phrase that starts the clock: "Please treat this as a formal complaint and send me a final response."

That last line matters most. Until the word complaint appears, the company formally has no complaint — it has a support query, and no deadline is running.

What evidence should you keep from day one?

Every body here, from FOS to CCW, works from documents rather than accounts of what was said.

Keep: dates and times of calls with the agent's name and the reference number; letters and chat transcripts, screenshotted before they are cleared; statements with the disputed lines marked; meter readings photographed with the date visible.

FOS specifically advises keeping a record of calls and events from the start. That is what turns a word-against-word dispute into a decided case.

What does it cost, and do you need a lawyer?

Nothing, and no. Every body listed here is free to consumers — they are funded by the industries themselves. Firms offering to "get your money back" for a percentage take a cut of what you would have received anyway.

English is the only real barrier. Write in short plain sentences: style does not affect the outcome, dates and amounts do.

What can an ombudsman not do?

It will not fine a company for your benefit — it restores the position rather than punishing. It will not tear up lawful terms you signed. It does not replace a court where the loss exceeds the limit.

And this matters: if you accept a final ombudsman decision, going to court afterwards for more is unlikely to be possible. Acceptance ends the story, so do the maths before you click accept.

What should you do today?

Write down the date you first contacted the company. Every deadline runs from it. If more than 8 weeks have passed — 6 for telecoms — and there is no final response, go to the ombudsman now; there is nothing left to wait for.

If the final response has arrived and you disagree, look at its date. For financial cases you have exactly 6 months, and it is not extended.

The deadlines and payment dates these disputes tend to hang on are collected in the ONLYWAY calendar.

Read also: UK credit history: how to build it and how to wreck it · Council tax: bands, discounts and what to do about arrears