Back-Billing Rules: Understanding the 12-Month Protection

At a glance

  • Great Britain’s back-billing rules protect households and qualifying microbusinesses against certain charges for energy used more than 12 months earlier.
  • They do not automatically cancel an old debt that was correctly billed or otherwise properly requested at the time.
  • Exceptions can apply where the customer obstructed accurate billing or behaved manifestly unreasonably.
  • Check the consumption dates, account history and supplier’s explanation before accepting or disputing the amount.

A catch-up bill can arrive after estimated readings, a communications problem or an account error. The important question is not simply whether the bill is large or the energy is old. It is whether the supplier is entitled to recover those particular charges in the circumstances.

This guide concerns Ofgem’s rules in Great Britain. It does not establish the outcome of an individual dispute or cover every business account.

On this page

What a back bill is

A back bill asks for payment for energy used earlier that was not accurately charged at the time. For example, a supplier may replace a series of low estimates with an actual reading and discover more consumption.

Ofgem’s current consumer guidance explains when the 12-month limit applies, including inaccurate or missing earlier billing, statements of account and Direct Debit undercollection. The protection concerns the period of consumption and the previous recovery history, not simply the date printed on the latest bill.

Old consumption and old debt are different

If energy used two years ago was accurately billed and the bill remained unpaid, the 12-month protection does not automatically erase it. Reissuing or chasing a valid earlier request for payment is different from first seeking to recover previously unbilled consumption.

Likewise, a bill covering 18 months is not necessarily wholly prohibited. Some charges may relate to the most recent 12 months, while others need checking against the protection. Ask for a period-by-period breakdown rather than treating the full balance as one indivisible amount.

For illustration, imagine a supplier first identifies an undercharge covering 18 months. If the protection applies, the older part may be excluded while valid recent charges remain payable. The actual calculation depends on dates, readings, earlier bills and recovery action; it is not automatically “six months written off”.

Exceptions and meter readings

Suppliers can rely on exceptions where obstructive or manifestly unreasonable behaviour prevented correct charge recovery. Examples can include preventing access to the meter or energy theft. A supplier should explain the behaviour and evidence it relies on.

Not submitting a meter reading is not, on its own, enough to remove the protection. Ofgem makes that distinction in its guidance on charge recovery for domestic and microbusiness customers. Keep records of readings you did supply, requests for help and access arrangements.

Do not assume that having a smart meter settles the issue either way. Communications can fail, and the supplier still needs to explain the actual account history.

Does it apply to a business?

The protection includes qualifying microbusinesses, not every organisation described informally as an SME. Business classifications used for different protections can differ.

Ask the supplier which definition and evidence it has used for your account. If the business is outside the protected category, other contractual or billing issues may still need investigating, but this particular limit should not be assumed to apply.

Gather the evidence

Create a simple chronology using:

  • Bills and statements, including earlier versions that were later cancelled.
  • The dates and amount of energy now being charged.
  • Actual and estimated readings, with meter serial numbers if relevant.
  • Payments, Direct Debit changes and account adjustments.
  • Reading submissions, access arrangements and earlier complaints.
  • Any explanation of why accurate billing did not happen sooner.

Separate energy charges from standing charges, tax, previous balances and payments. Ask the supplier to identify the earlier accurate bill or recovery action it says makes a disputed amount recoverable.

Ask for a clear review

Raise the issue with the supplier in writing. Identify the consumption period and amount you dispute, explain the apparent billing failure and request a review under the back-billing rules.

If money has already been collected, ask the supplier to review whether it was taken correctly and to refund or credit any error. Changing the collection method, for example through a Direct Debit, does not itself resolve whether a charge is valid.

Discuss the treatment of disputed and undisputed amounts while the complaint is investigated. Do not assume that making a complaint automatically stops all collections or removes ongoing energy charges.

A message you can adapt

Subject: Formal complaint—review of older energy charges

Please review the charges on bill [reference and date] for energy used between [dates]. The amount I dispute is [amount or bill lines].

I believe these charges may fall within the back-billing protection because [explain the missing or inaccurate earlier billing]. Please provide the readings, rates and consumption periods used, and identify any previous accurate bill, statement or charge-recovery action you rely on.

If you consider an exception applies, please explain it and provide the supporting evidence. Please correct the account and any money collected in error where the protection applies, and confirm the remaining balance and complaint reference.

Adapt the wording to the facts and attach relevant records through the supplier’s secure channel. Keep a copy of the message and response.

If the complaint is not resolved

Ask for the supplier’s final position and reasons. Eligible disputes can generally be referred to the Energy Ombudsman after eight weeks, or sooner with a deadlock letter; check the Ombudsman’s current scope and submission requirements.

If any remaining bill is unaffordable, ask separately about a sustainable payment arrangement and seek independent advice. A billing dispute and an affordability problem can exist together, and both need attention.

Sources and further reading

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