Financial experts and a high-profile politician have sounded the alarm over possible excess charges to UK energy consumers, which could amount to thousands of pounds. Amidst rising energy prices, it seems that some might have been paying more than they should.

On BBC Radio 4’s Money Box programme, an in-depth probe into back billing was featured. Despite a 2018 ban on this practice by energy companies, the show revealed that numerous customers have continued to receive these kinds of bills.

One Labour MP has decisively stepped up following the Money Box exposure of “evidence of wrongdoing”. Bill Esterson, MP for Sefton Central, fired off a strongly-worded letter to the chief executive of Ofgem insisting on action to assist affected constituents.

Martin Lewis, a trusted financial expert, joined the fray, drawing attention to a “real issue of breach”. He stressed that this problem has ensnared thousands of consumers, particularly in recent times, with some receiving demands for payment for energy usage dating back over a year.

Furthermore, there are accounts of consumers discovering that their accrued energy credit, tracked via apps or provider websites, has been inexplicably applied to settle back bills. If individuals find their advance payments utilised for energy used more than a year prior or if they get such backdated bills, they may be due a reimbursement.

The Guardian’s probe has revealed a trend of consumers being overcharged by their energy providers. British Gas’s parent company, Centrica, tops the list for most complaints filed with the Energy Ombudsman.

Countless customers are up in arms, with Citizens Advice dealing with more than 60,000 grievances about energy companies in 2024 alone. Despite billing processes being automated, it appears that “systemic issues” are to blame for the widespread inaccuracies.

British Gas described the outlawed back-billing practice on its website; the company stated: “Back-billing can be for any amount, but is limited to 12 months from finding an error to a corrected bill being issued. Under the Ofgem back billing rules, you can’t be charged for any unbilled energy used more than 12 months ago.”

The company added: “This protection may not apply if you’ve behaved obstructively or unreasonably in a way which prevents us from accurately billing you. For example, if you’ve prevented us on more than one occasion from taking a meter reading at your premises, or if you’ve stolen gas or electricity from us.”

MP Bill Esterson has raised concerns about this “breaching of legislation” by energy providers (in a letter to Ofgem).

Part of his letter reads: “You will be aware of the BBC Radio 4 Moneybox investigation into back-billing by energy companies and may have heard me on the media on Saturday. I have very strong feelings about this issue. The rules are very straightforward: energy companies, if they have not charged for energy consumed within 12 months, lose any right to do so. Moneybox has demonstrated that retailers continue to issue such bills.

“When challenged on their right to bill for this energy, the companies aggressively pursue payment and force customers to take cases to the Ombudsman. One reason I feel so strongly about this issue is that my supplier attempted to charge me for energy used well beyond the 12-month cut-off. Fortunately, I was able to navigate the complaints landscape and resolve the issue.

“My supplier told me that my experience was an isolated event due purely to human error. The Moneybox investigation has shown that this was not true. My concern is that not everyone will have the time, energy or knowledge to push their case and that the personal stories we hear about miss all of the people who simply paid the bill presented to them.”

Speaking on the Money Box programme in February 2025 was Dhara Vyas. She is the chief executive for Energy UK – which represents the energy industry.

On the radio programme, Dhara said: “To have to battle with a big energy company and feel like you’re not being heard is, of course, really bad. The back-billing rule was brought in because there was an issue and there are lots of different approaches to bills. In cases where things go wrong, suppliers have to take it seriously.”

Dhara also said that “multiple systems” are in use across the companies and that “things do go wrong sometimes”.

What you can do if you think you’ve overpaid

• Complain directly to the supplier – an email is advisable as you can then refer to the thread and what has been stated.
• If they will not help or if they refuse to help you, go to the Energy Ombudsman with your issue.
• You are also within your rights to ask an energy supplier for a Subject Access Request (SAR). This is a formal request for your personal data held by an organisation, which includes recordings of phone conversations – if you think you’ve been given incorrect information by a customer service operator.
• You can also ask your local Citizen’s Advice Bureau (CAB) to assist with the complaints process – or there are template letters about energy issues on the CAB website which you can download.