How long can an energy company backdate a bill in the UK?
For a newly recovered gas or electricity shortfall in Great Britain, the usual protection looks back 12 months from the first recovery action. An old unpaid accurate bill is different. Check which situation you have before disputing the dates.
The short answer
You should not accept “how long can they backdate a bill?” as a single yes or no question. First work out whether the supplier is correcting a recent catch-up issue or trying to recover usage from much older periods without having billed accurately when it should have done.
The 12 month back-billing protections are the key context for many household energy cases, but the facts still matter: the reading history, the billed period and why accurate billing did not happen earlier.
Use these pages too
Questions to ask in writing
- What exact dates does the charge cover?
- Which readings were used to build that balance?
- Why was accurate billing not issued earlier?
- Has the supplier assessed whether any part of the charge is outside the usual back-billing protections?
Official and reference sources
Frequently asked questions
Does every old-looking energy bill break the rules?
No. Some statements are recent catch-up corrections rather than improper recovery of very old usage.
What matters most in a backdated bill complaint?
The first recovery action for each shortfall, earlier accurate bills or statements, consumption dates, readings, tariffs and any evidenced exception. The date of the latest reminder alone is not enough.
Should I use this page or the main back-billing guide?
Use this page to distinguish a new backdated shortfall from an old unpaid bill. The main rules guide explains the condition and the date checker helps organise the consumption periods.
First decide whether these are new charges or an old debt
The domestic back-billing condition is SLC 21BA. It concerns recovery of previously unbilled usage and relevant supply charges outside a calendar 12-month window, subject to exceptions. It is not a general rule cancelling every debt when it becomes one year old.
- New shortfall: ask when the supplier first sought the correct amount for those units and charges. That recovery date is the starting point for the date check.
- Earlier accurate unpaid bill: ask for its issue date, supply period, readings and charges. A supplier can continue seeking payment for charges previously recovered in compliance with the condition; a later reminder does not automatically create fresh protection.
- Estimated bills: their mere existence does not prove that the correct amount had already been billed. Ask how the correction differs from the amounts previously stated.
- Conduct exception: ask what specifically prevented accurate billing. Ofgem says simply failing to notice estimates or not responding to requests to submit readings is not the intended exemption.
For the full conditions, see the back-billing rules guide. Use the date checker to organise dates, not to decide an entitlement.
What changes the answer?
| Situation | Evidence to request |
|---|---|
| You received an accurate bill for the same charges earlier | The original bill and proof of which units, standing charges and payments it covered. |
| The supplier alleges obstruction | Meter-access attempts, communications and the reason it could not recover the correct amount. Missing readings alone do not establish the exception. |
| The account moved to a new supplier or debt collector | Which supplier originally billed each period and when. Changing the collector does not itself establish a fresh recovery date. |
| You moved out | Your liability end date and final reading as well as the first recovery history. Age and liability are separate checks. |
The condition applies to recovery action from 1 May 2018. Northern Ireland, heat-network bills and business eligibility need separate guidance. This page addresses household gas and electricity in Great Britain.
A later reminder is not necessarily a new starting date
Suppose a new shortfall is first sought on 19 October 2026, for consumption from 19 April 2025 through 18 October 2026. The calendar cut-off is 19 October 2025: 183 days are older and 365 fall on or after it. Those counts identify periods to examine; they do not calculate money to remove.
Now suppose the same charges had already been accurately billed in a way that complied with the rule on 1 July 2026. An October reminder does not let you ignore that earlier recovery action. Ask for both documents and check whether the amounts and units really are the same.
Do not apply today's tariff to several old years or prorate the whole debt by calendar days. Ask for the actual tariff periods, consumption, standing charges, credits and payments. The back-billing checker exports the dates and evidence questions to help you request that breakdown.
Ask for the first recovery history in writing
Adapt this to your account; it does not assume the older amount is automatically protected.
Subject: Backdated energy charges — request for breakdown Dear [supplier], Please explain the charges on my bill dated [date] for [amount]. Provide the consumption dates, readings, tariff periods, standing charges, credits and payments used. For each newly recovered shortfall, please identify the first date you sought the correct amount and supply earlier bills or statements for the same charges. Explain your assessment under SLC 21BA and provide evidence for any exception relied on. Please confirm what amount is undisputed and how collection activity on the disputed portion will be handled while you investigate. Please record this as a complaint and confirm the complaint reference and start date. Yours faithfully, [name]
Keep a copy and attach dated readings or earlier statements where relevant. Use the full complaint template if you need a longer evidence checklist. An open complaint does not automatically pause collection or remove liability.
Frequently asked questions
Is the answer simply twelve months?
No. Twelve months is the usual window for newly recovered older charges under the condition, subject to exceptions. An old unpaid accurate bill can still be pursued. Check first recovery history and any evidenced exception.
Does the limit apply to a final bill after I move out?
The same back-billing condition can be relevant to household final bills. Check when the supplier first sought the new charges, earlier bills for the same amounts, your liability end date and final reading. Moving out alone does not settle whether charges are protected.
What about debt already passed to a collection agency?
Raise the complaint with the supplier, not the agency, and tell both in writing that the balance is disputed under the back-billing rules. See how long an energy company can chase a debt.