Not Billed for Energy in Over a Year?
If you have not received an accurate bill for a long time, do not just argue that the amount feels unfair. Identify the billing gap, the supply period and which charges may be older than 12 months.
Use together
The short answer
A long gap without accurate bills is a red flag for back-billing checks. Build a timeline of statements, estimated readings, actual readings and supplier messages before deciding what amount to dispute.
Timeline to build
Last accurate bill
Find the last bill based on reliable readings.
Missing period
Mark months with no bill or only estimates.
Supplier contact
Save messages where you gave readings or asked for a bill.
New large bill
Separate current usage from older usage.
Ask for a period breakdown
Please identify any charges relating to energy used more than 12 months before the bill date.
Please explain whether you consider those older charges recoverable under back-billing rules and why.
Build the timeline before you write anything
A year-long billing gap is one of the strongest back-billing positions there is, and people routinely weaken it by leading with how shocking the amount is. The amount is not the argument. The gap is.
Open a single document and put these five columns across the top. Fill it in from your bank statements, your email archive and your online account, oldest first.
| Date | What arrived | Reading type | Amount | Evidence I hold |
|---|---|---|---|---|
| 12 Mar 2025 | Last accurate bill | Actual | £98.40 | PDF saved |
| Apr 2025 – May 2026 | Nothing | — | — | Bank statements show DD continued |
| 18 Sep 2025 | I submitted a reading via the app | Customer | — | Screenshot |
| 03 Jun 2026 | Catch-up bill | Actual | £2,140.00 | PDF saved |
That table is your complaint. Paste it straight into the letter. It does three things at once: it shows the gap, it shows you tried, and it gives the Ombudsman a document rather than a narrative if it gets that far.
The rule itself, in one paragraph
Standard Licence Condition 21BA is the back-billing rule for domestic customers. It says a supplier must not charge you for gas or electricity used more than 12 months before the date of the bill, where the supplier is the reason you were not billed accurately during that period. It has applied to every licensed supplier in Great Britain since 1 May 2018. Microbusinesses get the same protection under SLC 7A.
Two things in that sentence do most of the work, and most complaints are lost on them:
- “12 months before the date of the bill.” The clock runs backwards from the bill, not from when you noticed, not from when the meter was last read, and not from when you first complained. A bill dated 3 September 2026 cannot properly charge you for energy used before 3 September 2025 if the supplier was at fault.
- “Where the supplier is the reason.” The protection is about supplier failure. If the supplier can show you obstructed accurate billing — refused meter access, ignored repeated reading requests, or behaved in a way the rule calls manifestly unreasonable — the protection can fall away for that period.
Source: Ofgem, Modification of the electricity and gas supply licences to introduce rules on backbilling, in force 1 May 2018. Always check the current licence text before quoting a condition number to a supplier — conditions are amended.
What a realistic outcome looks like
It is worth calibrating before you start, because unrealistic expectations lead people to reject reasonable offers and then lose at the Ombudsman.
Likely
The portion older than twelve months is removed. The rest is rebilled correctly and spread over an interest-free plan. Often a goodwill payment of £50–£150 for the service failure.
Possible
A larger goodwill amount where you can show you repeatedly submitted readings or chased for a bill and were ignored. Documented chasing is what moves this number.
Unlikely
The whole balance written off. Energy you used within the last twelve months is normally payable, and asking for everything tends to get the whole complaint treated as unreasonable.
Only if you push
Removal of the standing charges attached to the protected period, and correct apportionment of consumption across the rate periods it actually occurred in. Neither happens automatically.
The letter, written out in full
Copy, fill in the square brackets, send by email
Numbering the requests matters more than the tone. A numbered list is harder to answer with a paragraph of general reassurance, and if it goes to the Ombudsman, it shows exactly which questions the supplier declined to answer.
What happens after you send the letter
Day 0 — written complaint
Send it by email or the supplier's complaint form so there is a timestamp. Ask for a complaint reference. Keep paying the undisputed part.
By day 56 — eight weeks
Either they resolve it, or you can take it to the Energy Ombudsman. A deadlock or “final response” letter unlocks that door sooner.
Then 28 days to implement
If the Ombudsman upholds the complaint, the supplier has 28 days to actually do what was decided. The decision binds the supplier, not you.
Confirmed for the near future: eight weeks becomes six
On 17 June 2026 the government published its response to the Fairer, faster redress in the energy market consultation and confirmed two changes: the wait before you can escalate drops from 8 weeks to 6 weeks, and the Ombudsman's own window for issuing a decision drops from 6 weeks to 4 weeks. Redress schemes will also get the power to penalise suppliers who fail to implement a decision on time.
None of this is in force yet. The response says the changes will be made “as soon as reasonably possible and certainly no later than Royal Assent for the Energy Independence Bill”. Until then, plan around eight weeks — but if your complaint is running into late 2026, check the current position before you assume you have to keep waiting.
Frequently asked questions
What if I used the energy?
Using energy does not automatically decide whether older charges can be recovered. The back-billing rules and facts matter.
What if I never sent readings?
That can affect the analysis. Gather evidence of whether you had access to readings, whether the supplier asked and whether you cooperated.
Can I ask for a payment plan?
Yes. Even if part of the bill is valid, ask for affordable payment support in writing.
I kept paying by direct debit the whole time. Does that change anything?
It helps you. Continued payment shows you were not avoiding the account, and it means part of the balance is already covered. Ask for a statement showing every payment received against the period, because these are sometimes not applied to the catch-up bill correctly.
What if I chased them for a bill and nothing happened?
That is the most valuable evidence you have. Find the emails, chat transcripts or call dates, list them in the timeline, and ask the supplier to produce its own contact record for the same period. A mismatch between the two is very hard for them to explain.
Should I stop paying until it is sorted?
No. Name the undisputed amount, keep paying that, and ask for collection activity on the disputed portion to be paused in writing. Stopping payment altogether turns a billing complaint into an arrears case.
Official sources used for this page
BillDecoded translates official process and billing information into practical checks. It is not affiliated with the Ombudsman, Ofgem, Citizens Advice, Which? or any supplier.