Got the wrong bill from British Gas? Here is how to fix it.
This guide explains who British Gas is, the most common reasons your bill might be wrong, the law that protects you (especially the 12-month back-billing rule and the new prepayment meter compensation programme), and how to send British Gas a proper complaint letter by Royal Mail.
About British Gas Trading Limited
British Gas is the oldest energy supplier in the UK. The company's history goes all the way back to 1812, when the Gas Light and Coke Company started lighting London's streets. In 1948, after the Second World War, the government took the gas industry into public ownership. In 1986 the Thatcher government sold it back to the public as British Gas plc. In 1997 the company split into two: Centrica (which kept the British Gas brand for selling gas and electricity to homes) and BG plc (the upstream gas exploration business). Today's British Gas has serviced UK homes continuously for over 200 years.
British Gas Trading Limited is the company that supplies you with gas and electricity. The Companies House number is 03078711 and the registered office is at Millstream, Maidenhead Road in Windsor, Berkshire. The full parent company is Centrica plc, which is listed on the London Stock Exchange (ticker CNA) and is one of the 100 biggest UK companies (FTSE 100 member). Centrica's group revenue in 2025 was £21.5 billion. The current Group CEO is Chris O'Shea, and the Managing Director of UK Home is Matthew Bateman.
British Gas serves around 10 million UK homes. It was the largest UK electricity supplier until 2024, when Octopus Energy overtook it. It IS still the largest UK gas supplier. In Scotland the company trades as "Scottish Gas" (same legal entity, different brand name). The Republic of Ireland operation trades as Bord Gáis Energy. British Gas also sells HomeCare boiler insurance through a separate legal entity called British Gas Insurance Limited.
Registered office
British Gas Trading LimitedMillstream, Maidenhead Road
Windsor, Berkshire
SL4 5GD
United Kingdom
Companies House number: 03078711 · Incorporated: 26 August 1995 · Parent: Centrica plc (LSE ticker CNA, FTSE 100) · Regulator: Ofgem (Office of Gas and Electricity Markets) · Ombudsman scheme: Energy Ombudsman (run by Ombudsman Services)
Group structure
Centrica plc (parent)
This is the public company that owns British Gas. Listed on the London Stock Exchange under the ticker CNA and a member of the FTSE 100 (the 100 biggest UK listed companies). Headquartered in Windsor, Berkshire. Founded on 17 February 1997 when the original British Gas plc split into two companies. Centrica is also the owner of Bord Gáis Energy in Ireland and Centrica Energy (an upstream gas business). Annual revenue was £21.5 billion in 2025.
LSE ticker CNA. FTSE 100 member.British Gas Trading Limited
This is the company that holds the Ofgem gas and electricity supply licences. If your bills come from "British Gas", "Scottish Gas" or "Centrica" for energy, your contract is with this company. Companies House number 03078711. This is also the company you serve with a legal claim about energy bills.
Companies House 03078711. Ofgem-licensed supplier.British Gas Services Limited and British Gas Services (Commercial) Limited
These two companies handle the non-energy side, mainly HomeCare boiler servicing and repairs. British Gas Services Limited deals with consumer HomeCare. British Gas Services (Commercial) Limited (Companies House 07385984) deals with business customers. If your complaint is about a boiler service, repair or HomeCare contract, the right legal entity is one of these, not British Gas Trading.
British Gas Insurance Limited
This is the entity that ACTUALLY underwrites the HomeCare insurance product. Companies House number 06608316. It is regulated by the Financial Conduct Authority (FCA) and the Prudential Regulation Authority (PRA), under FCA Financial Services Register number 490565. So HomeCare complaints have an extra escalation route: the Financial Ombudsman Service (FOS), which is different from the Energy Ombudsman. The route depends on what exactly went wrong.
Common reasons your British Gas Trading Limited bill might be wrong
- 1The smart meter has not been sending readings. This is the biggest single cause of wrong bills across all UK energy suppliers, and British Gas is no exception. The bill is then based on an estimate, which is often too high in winter or too low in summer. You can check by reading the meter yourself and sending it to British Gas.
- 2You were back-billed for more than 12 months. British Gas sometimes issues a big catch-up bill after months of estimates. Standard Licence Condition 21BA says they CANNOT bill you for energy used more than 12 months ago if the missed billing was their fault. This is explained in detail below.
- 3A prepayment meter was forcibly installed and you should now be in line for compensation. If a British Gas prepayment meter was installed under court warrant in your home between 2018 and 2023, you may be eligible for compensation under the new £112 million settlement Ofgem agreed with British Gas in May 2026. See the dedicated block further down.
- 4HomeCare charges added to your energy bill. British Gas sometimes adds HomeCare insurance charges to the energy bill. If you cancelled HomeCare but the charges are still appearing, or you never agreed to HomeCare, those charges should not be there.
- 5Direct debit went up without proper justification. British Gas has to give you fair notice and a clear breakdown if they want to raise your monthly payments. Big unexplained jumps can be challenged. Citizens Advice publishes specific guidance on this.
- 6A previous occupant's debt was added to your account. If you moved into a new property, debts run up by previous occupants are NOT yours. You only owe British Gas for energy used since you moved in.
The energy billing rules that protect you
| Rule | What it means | Source |
|---|---|---|
| 12-month back-billing rule | If your energy supplier did not bill you accurately because of their own mistake, they cannot now charge you for energy used more than 12 months ago. | Standard Licence Condition 21BA (domestic), SLC 7A (microbusiness). In force since 1 May 2018. |
| Standards of Conduct | Suppliers must treat you fairly, give you clear information, and make sure billing is accurate. | SLC 0 and 0A. |
| Priority Services Register | If you are vulnerable, you get extra protections including more regular meter reads. | SLC 26. |
| Default Tariff Cap | Limits the amount per unit and standing charge if you are on a default or "standard variable" tariff. | Reset every quarter by Ofgem. |
British Gas is signed up to all of these rules because they hold a UK gas and electricity supply licence from Ofgem. They are also bound by the new Prepayment Meter Code of Practice, which became a formal licence condition in late 2023 following the prepayment meter scandal explained next.
The 2026 prepayment meter compensation programme (special to British Gas customers)
In May 2026, Ofgem announced the LARGEST settlement it has ever secured against any energy supplier. British Gas agreed to pay £20 million in direct compensation AND write off up to £70 million of energy debt owed by vulnerable customers, with a total programme value of up to £112 million. This followed a three-year Ofgem investigation that began in February 2023, after The Times newspaper revealed that debt agents working for British Gas had forced their way into vulnerable customers' homes to install prepayment meters under court warrants.
The investigation covered British Gas activity from February 2018 to February 2023. Ofgem found that British Gas knew about problems as far back as 2018 and was warned again in 2021 but did not act. The settlement requires British Gas to: (1) directly compensate customers who already complained between 2022 and 2023, (2) extend compensation for the first time to anyone affected between 2018 and 2021, (3) write off up to £70 million in energy debt held by vulnerable customers, and (4) carry out a comprehensive review of customer records from the period.
What this means for you: If a British Gas prepayment meter was installed under a court warrant in your home between February 2018 and February 2023, especially if you were elderly, lived with young children, had a disability or were otherwise vulnerable, you may be entitled to a payment. Ofgem says British Gas will contact eligible customers automatically. But if you believe you should be on the list and have NOT been contacted, send a formal letter quoting the Ofgem settlement of May 2026. Reference your address at the time and the date the meter was installed.
Your rights
Standard Licence Condition 21BA (the back-billing rule)
This is the big one for fixing wrong bills. British Gas cannot bill you for gas or electricity used more than 12 months ago if British Gas was at fault for not billing accurately. The rule lives in the Standard Conditions of Electricity Supply Licence and the Standard Conditions of Gas Supply Licence, both made under the Electricity Act 1989 and the Gas Act 1986. It has been in force since 1 May 2018.
Standard Licence Conditions 0 and 0A (Standards of Conduct)
These set out broad rules about how British Gas has to treat you. They have to be fair, give you clear information, use plain language, and make sure billing is accurate. Breaches of these standards were part of the Ofgem prepayment meter investigation.
Standard Licence Conditions 27, 28 and 28B (prepayment meters and warrant access)
These specifically cover how British Gas can install prepayment meters and access your home. The 2026 Ofgem settlement was about British Gas breaching these rules. Ofgem has now strengthened the Prepayment Meter Code of Practice and made it a licence condition all suppliers must follow.
Standard Licence Condition 26 (Priority Services Register)
If you are over 65, disabled, have a long-term illness, are pregnant, have children under 5, or struggle with English or money matters, you can sign up to the Priority Services Register. This gives you extra protections, including more regular meter reads (so estimates do not pile up) and protection from disconnection. British Gas was specifically criticised by Ofgem in the prepayment meter scandal for failing to check whether customers were on the Priority Services Register.
Consumer Rights Act 2015, sections 49 and 51
This is the general consumer law that applies to all services in the UK, including energy and HomeCare. Section 49 says services must be performed with reasonable care and skill. Section 51 says the price must be reasonable if it is not agreed in advance.
How long do you have to challenge a bill?
The Limitation Act 1980 gives you 6 years to bring a court claim about a contract dispute in England, Wales and Northern Ireland (5 years in Scotland). But for an energy bill, use the back-billing rule and the Energy Ombudsman first. For the prepayment meter compensation specifically, the May 2026 Ofgem settlement is the active programme to apply under.
Common British Gas Trading Limited situations
You had a prepayment meter forcibly installed between 2018 and 2023
This is the special British Gas situation. Under the May 2026 Ofgem settlement, you may be entitled to direct compensation AND a write-off of any debt that built up afterwards. Ofgem says British Gas will contact eligible customers automatically. If you have NOT been contacted and you think you should be, send a formal letter to British Gas referring to the May 2026 Ofgem settlement, your address at the time, and the approximate date of meter installation. Mention if you were elderly, vulnerable, had young children, a disability, or were on the Priority Services Register.
You got a huge catch-up bill after months of estimates
This is the classic SLC 21BA case. If British Gas has been sending you estimated bills and then suddenly sends you a corrected bill for more than 12 months of usage, write to them quoting SLC 21BA. Ask them to cap the bill at the 12 months immediately before the corrected bill date. You only have to pay for that 12-month window. The earlier part has to be written off.
Your smart meter has not been sending readings
Smart meters sometimes lose their signal. When that happens, British Gas's system uses estimates. The first thing to do is take a manual reading and send it to British Gas. If they failed to spot the problem for many months and now want to back-bill you, the back-billing rule applies. British Gas had a duty to notice and fix the problem; the back-billing rule does NOT only apply if you complained.
HomeCare charges are wrong or you cancelled and they kept charging
HomeCare is sold by British Gas Services Limited and underwritten by British Gas Insurance Limited (a different legal entity, FCA/PRA regulated). If HomeCare charges are still on your bill after you cancelled, or you never agreed to HomeCare in the first place, write to British Gas Services. The right escalation route for HomeCare disputes is the Financial Ombudsman Service (FOS), NOT the Energy Ombudsman. This is because HomeCare is an insurance product.
Your direct debit went up sharply
British Gas has to follow Standard Licence Condition 31I when changing your direct debit. They must give fair notice and a clear breakdown of why. If your usage has not changed but your monthly direct debit went up a lot, demand a written explanation. Your credit balance, recent usage and current tariff should all line up with the direct debit amount.
A previous tenant's debt was added to your account
This sometimes happens during a property move-in. The previous occupant's debt should NEVER end up on your account. You only owe British Gas for energy used since you moved in. Send British Gas a letter with your tenancy agreement start date (or completion date if you bought the property) and demand the historical balance be removed.
British Gas keeps ignoring your complaint
After 8 weeks of unresolved complaint or after getting a final "deadlock" letter from British Gas, you can take the case to the Energy Ombudsman free of charge. The Energy Ombudsman makes binding decisions. British Gas has had a poor record on complaint resolution historically. A formal letter sent first by Royal Mail makes the Ombudsman case much stronger.
Send your British Gas Trading Limited complaint by Royal Mail
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Frequently asked questions
What is the back-billing rule and does it apply to British Gas?
Yes, it applies to every UK gas and electricity supplier including British Gas. Standard Licence Condition 21BA says that if British Gas failed to bill you accurately because of their own mistake, they cannot now charge you for energy used more than 12 months ago. So if you suddenly receive a catch-up bill for 18 months or two years of energy, write to British Gas quoting SLC 21BA and demand the bill be capped at 12 months.
What is the 2026 prepayment meter compensation settlement about?
In May 2026, Ofgem announced the largest energy enforcement settlement ever. British Gas agreed to pay £20 million in compensation and write off up to £70 million in vulnerable customer debt, totalling up to £112 million. This was after a three-year investigation following a 2023 Times newspaper exposé. The settlement covers customers who had prepayment meters forcibly installed between February 2018 and February 2023. If you were affected, British Gas should contact you automatically. If not, send a formal letter referencing the settlement.
Is HomeCare the same as my British Gas energy bill?
No. HomeCare is a separate insurance product. It is sold by British Gas Services Limited and underwritten by British Gas Insurance Limited (a different legal entity, FCA/PRA regulated). If your dispute is about HomeCare cover (a missed appointment, a refused claim, charges still appearing after you cancelled), the right escalation is the Financial Ombudsman Service (FOS), not the Energy Ombudsman. If the dispute is about energy charges only, use the Energy Ombudsman.
My smart meter stopped sending readings. Whose fault is that?
Smart meter signal problems are usually the supplier's responsibility. British Gas has a duty to monitor data and fix problems they spot. If your meter stopped sending readings and British Gas failed to notice for many months, that is THEIR fault, not yours. You can use the 12-month back-billing rule. You should also try to send manual readings whenever you spot a problem.
How do I escalate to the Energy Ombudsman?
First make a formal complaint to British Gas in writing. They have 8 weeks to resolve it. If they refuse or you have a final "deadlock" letter, you can take the case to the Energy Ombudsman at energyombudsman.org or by calling 0330 440 1624. The service is free for customers and binding on British Gas. The Ombudsman can order British Gas to pay you compensation, write off charges, or apologise.
What about Scottish Gas — is that the same as British Gas?
Yes. Scottish Gas is just the brand name used by British Gas Trading Limited in Scotland. It is the same legal entity (Companies House 03078711). Scottish Gas customers have the same rights and the same complaints route. Quote "British Gas Trading Limited" on any formal letter even if your account is branded Scottish Gas.
How long do I have to make a complaint?
There is no strict deadline for raising a complaint directly. But there are two important time limits in the background. The 12-month deadline applies for taking a case to the Energy Ombudsman: you have to escalate within 12 months of getting British Gas's final response. The 6-year deadline applies for going to court (5 years in Scotland) under the Limitation Act 1980. Acting sooner is always better.
Can I get British Gas to refund a credit balance to my bank?
Yes. If your British Gas account is in credit (you have paid more than you used), you can ask for the credit to be refunded to your bank account. British Gas's standard practice is to refund credit balances over a set threshold at the annual review, but you can ask any time. The money is yours.
Free help and what to do next
Energy Ombudsman
Free, binding dispute resolution for energy customers. After 8 weeks of unresolved complaint or a final response from British Gas, take your case here. Decisions are binding on British Gas. Free for you to use. Helpline: 0330 440 1624.
Visit website →Ofgem (the regulator)
The UK energy regulator. Does not handle individual complaints (that is the Ombudsman's job), but enforces the licence conditions. Ofgem secured the £112 million British Gas prepayment meter settlement in May 2026. Worth reporting persistent bad behaviour to add to the enforcement record.
Visit website →Financial Ombudsman Service (for HomeCare complaints only)
For complaints about HomeCare insurance products (not energy bills), the route is the Financial Ombudsman Service. British Gas Insurance Limited is FCA-regulated under register number 490565, which is why this scheme applies for HomeCare disputes. Helpline: 0800 023 4567.
Visit website →Money Claim Online (MCOL)
The online court service for England and Wales. Use this if British Gas refuses to follow an Ombudsman decision, or to sue British Gas directly. You have 6 years from the date of the disputed bill to sue (5 in Scotland).
Visit website →Ready to challenge your British Gas Trading Limited bill?
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