The back-billing rule
Ofgem bans domestic and microbusiness energy suppliers from charging you for gas or electricity used more than 12 months ago if you hadn’t been correctly billed for it. You’re protected if any of these apply:
- they never sent you an accurate bill for that energy (even if you asked);
- they never told you the charges were due via a proper statement of account;
- your Direct Debit was set too low to cover what you were actually using.
This is now an enforceable licence condition, so it applies whoever your supplier is. It covers the classic shock scenarios: a long run of estimated bills, a switch or smart-meter mix-up, or a supplier “catching up” after years of under-charging.
The one exception
The protection doesn’t apply if you actively prevented accurate meter readings — for example by blocking access to the meter or tampering with it. If the under-billing was the supplier’s fault or down to estimates, the 12-month limit stands.
Source verification
Primary sources: Ofgem (“What to do if you get a back bill” and the decision banning back-billing beyond 12 months) and Citizens Advice. Last verified 20 June 2026. Confidence: High — suppliers cannot bill domestic or microbusiness customers for energy used more than 12 months ago where the customer wasn’t correctly billed or informed, it is an enforceable licence condition applying to all suppliers, and the main exception is where the customer prevented accurate meter readings. The rule caps how far back charges can go but doesn’t wipe genuine recent usage, for which an affordable payment plan can be requested. SortedUK is independent — not a government service, an energy supplier or a law firm, and this is general information, not legal advice.
Energy back bills — common questions
My bills were estimated for two years — do I owe it all?
No. If you weren’t given accurate bills, the supplier can only charge for the last 12 months’ usage; anything older should be removed under the back-billing rule. Quote the rule in writing and ask for a corrected bill.
Does the rule apply to my business?
It applies to domestic customers and microbusinesses. Larger businesses aren’t covered by the back-billing rule, though other contract and fairness protections may still help.
They’re threatening to disconnect me — can they?
If you engage and agree an affordable plan, you normally can’t be disconnected, and there are stronger protections if you’re vulnerable (sign up to the Priority Services Register). Get free advice from Citizens Advice if they pressure you.
What if the supplier won’t budge?
Make a formal complaint, then after 8 weeks (or a deadlock letter) take it free to the Energy Ombudsman, whose decision binds the supplier. Keep all your correspondence.