Back-billing: you may not have to pay old energy charges
The short answer
Your supplier can't usually bill you for gas or electricity used more than 12 months ago if you weren't billed correctly and it wasn't your fault. Ofgem made this a rule in 2018.
Checked 7 October 2026Written by the MyBillChecker team
It applies when your supplier didn't bill you correctly, for example because of long-running estimates, a billing system error or a meter it failed to read. Not giving readings yourself doesn't count as your fault.
When it doesn't
If you blocked access to the meter, tampered with it or took energy illegally, the supplier can bill further back.
Template: back-billing letter
Template letter
Subject: Back-billing, account [number]
Your bill dated [date] includes charges for energy used before [date 12 months before the bill]. I wasn't correctly billed for this period and it wasn't due to my behaviour. Under Ofgem's back-billing rule, please remove these charges and send a corrected bill. If this isn't resolved within 8 weeks, I'll refer it to the Energy Ombudsman.
Frequently asked questions
Does it apply to businesses?
Yes, to microbusinesses too.
What if I've already paid?
Complain anyway. Ask for a refund of charges for use over 12 months old.
