UK Energy Suppliers

The UK domestic energy market is regulated by Ofgem, the Office of Gas and Electricity Markets. All domestic suppliers must hold a supply licence from Ofgem and comply with its rules on pricing, billing, customer service standards, and the treatment of vulnerable customers.

Customers have been free to choose their energy supplier since the market was fully deregulated in 1996. Switching supplier does not affect the physical delivery of gas or electricity. That is handled by separate regional distribution networks which are independent of your supplier.

The largest suppliers by customer numbers, including British Gas, E.ON Next, EDF Energy, Octopus Energy, and OVO Energy, together serve the majority of UK households. These suppliers typically offer a broad range of tariff types including fixed deals, variable tariffs, prepayment options, and specialist products for electric vehicle owners.

Smaller independent suppliers entered the UK market in significant numbers from the mid-2000s onwards, attracted by deregulation and the opportunity to compete on price and service. Several have grown substantially. Octopus Energy, for example, now serves more than 7 million customers and is one of the largest suppliers in the UK.

A number of suppliers focus specifically on renewable energy tariffs. Ecotricity, Good Energy, and 100Green source electricity from renewable generators and publish detailed fuel mix disclosures. Other larger suppliers also offer green tariff options within their broader product range.

The energy crisis of 2021 and 2022 saw a significant number of UK suppliers exit the market. Wholesale gas prices rose sharply and many smaller suppliers, whose business models relied on buying energy on the spot market, were unable to sustain supply. More than 60 suppliers ceased trading during this period.

Under Ofgem's Supplier of Last Resort process, customers of failed suppliers were automatically moved to a replacement supplier. Supply was never interrupted. Any credit balances customers held were protected under this process.

Notable suppliers that ceased trading during this period included Bulb Energy (1.5 million customers, transferred to Octopus Energy), SSE (3.5 million customers, transferred to OVO Energy), and npower (6.5 million customers, transferred to E.ON Next).

Each supplier profile below covers the supplier's background, the tariff categories they offer, their Trustpilot rating, and contact details for billing and complaints. Profiles do not show live tariff pricing. That changes regularly and depends on your postcode and usage.

To compare what each supplier is currently charging at your address, use the partner comparison tool. It pulls live tariffs specific to your postcode and usage level.