Ofgem opened an investigation into ScottishPower Energy Retail Limited on Thursday 5 November 2026. It’s looking at whether the supplier followed the rules on backbilling, supporting customers in vulnerable situations, assessing customers’ ability to pay, and treating customers fairly. Most of the rules named are about household customers, but the backbilling rule also protects microbusinesses. Ofgem says opening the investigation doesn’t mean it has found ScottishPower broke any rules. You don’t need to do anything, but if you’ve had a large catch-up bill from any supplier, it’s worth checking your rights.
What is Ofgem investigating?
Every energy supplier holds a licence, and its standard licence conditions (SLCs) are the rules it must follow to keep that licence. Ofgem is checking ScottishPower against five of them, for its gas and electricity supply licences:
- SLC 0: treating domestic customers fairly, including those in vulnerable situations.
- SLC 21BA: the ban on backbilling customers for energy used more than 12 months earlier.
- SLC 26: keeping a Priority Services Register, the list of customers who need extra help, sharing that information and offering the support.
- SLCs 27.8 and 27.8A: helping customers who are struggling to pay, including taking account of what they can afford when setting up debt repayments.
Ofgem hasn’t said which period the investigation covers, how many customers are affected, or whether any business customers are involved. An Ofgem spokesperson told The Independent: “Ofgem expects suppliers to treat their customers fairly and respectfully, including ensuring bills are accurate and that appropriate support is offered for people in vulnerable circumstances.” Ofgem says it will report its findings after it has assessed all the relevant evidence.
What is backbilling?
A backbill is a catch-up bill: one your supplier sends when you haven’t been charged correctly for the energy you used. It usually comes from a billing system error, or from estimated bills that a later meter reading shows were too low.
In 2018, Ofgem banned suppliers from backbilling for energy used more than 12 months ago. The ban covers domestic and microbusiness customers. It came into force for households in May 2018 and for microbusinesses in November 2018. A supplier can still bill further back if a customer has been obstructive or acted unreasonably, for example by blocking access to the meter or tampering with it. Ofgem says customers aren’t at fault just for not giving meter readings.
When Ofgem brought the ban in, it said the median household backbill was £1,160, based on a Citizens Advice sample from 2016/17, and that extreme cases had topped £10,000. Those are household figures from 2018, not business ones.
What happens next?
Ofgem hasn’t set a date. It says it will report its findings once it has assessed all the relevant evidence.
Supplier fines could also be about to get bigger. The Energy Independence Bill, introduced in Parliament on 4 November 2026, would set the maximum fine for a supplier’s breach at the greatest of 10% of its turnover, £5 million, or an amount worked out from what it gained from the breach. That’s in the Bill as introduced, and it won’t apply until the Bill becomes law.
What does this mean for your business?
This investigation is mainly about household customers. But the backbilling rule protects microbusinesses too. If you’re a microbusiness and your supplier bills you for energy used more than 12 months ago, and you haven’t stopped them reading your meter, the rule says they can’t charge you for it.
Here’s what to check:
- Your readings: if your bills keep saying “estimated”, send your supplier actual meter readings (our guide to reading your business energy bill shows how to spot an estimated reading), and take a dated photo of the meter so there’s no argument about the reading later.
- Any catch-up bill: don’t pay it straight away, and don’t ignore it. Look at the dates of the energy it charges for, and send it to us.
- Your contract dates: we always advise arranging your next contract as early as possible, normally 12 months before your renewal date, so you can take advantage of forward pricing.
Send us any catch-up bill and we’ll check the dates it covers and the meter readings it’s based on. If it reaches back more than 12 months and your business is a microbusiness, we’ll tell the supplier it breaks the backbilling rules and take the error up for you.
Talk to our energy experts
Got a bill that doesn’t look right? Book an appointment with our Energy Team, get a quote, or call us on 01273 914000.