The UK's Main Home Energy Suppliers: A 2026 Guide

The UK’s home energy market has changed significantly in recent years. The energy crisis of 2021-22 saw around 30 suppliers go out of business, leading to a period of major consolidation. For households, this means fewer suppliers to choose from, but the landscape is still competitive, with a mix of long-established names and newer, fast-growing companies vying for your custom.

This guide provides an overview of the main energy suppliers for UK households in 2026. We’ll look at who owns the largest share of the market, how they compare on customer service, and what you should consider when deciding which company is the right fit for your home.

The UK Energy Market in 2026

As of March 2026, there are 17 active domestic energy suppliers in Great Britain. The market is dominated by a handful of large companies, often referred to as the ‘Big Six’, though the members of this group have shifted over time. The current major players are Octopus Energy, British Gas, E.ON Next, OVO Energy, EDF Energy, and ScottishPower.

The market is overseen by the regulator, Ofgem, which sets the energy price cap. This cap limits the unit rates and standing charges that suppliers can bill customers on a standard variable tariff (SVT). For the period 1 October to 31 December 2026, Ofgem has set the price cap at £1,723 per year for a typical household paying by Direct Debit. This represents a 4% increase from the previous quarter, driven by higher wholesale gas prices. It’s crucial to remember this is not a cap on your total bill - if you use more energy, you will pay more.

The chart below shows how many licensed suppliers have been active in the domestic market since 2004. For most of the 2000s there were only around a dozen. That changed after 2010, when Ofgem lowered the barriers to entry and a wave of new challengers arrived, taking the total to a peak of 70 in 2018. The energy crisis then reversed it almost overnight: when wholesale gas prices surged in late 2021, around 30 suppliers went bust within a year, and their customers were moved to surviving firms under Ofgem's Supplier of Last Resort process. The number has been drifting down ever since, from the mid-20s to the 17 active today - which is why the market is once again dominated by a handful of large companies.

Number of Active Domestic Energy Suppliers

UK Energy Supplier Market Share

The balance of power in the energy market has seen a dramatic shift, with Octopus Energy growing rapidly to become the UK’s largest supplier. The tables below show the market share for both electricity and gas held by the main providers.

Electricity Customers & Market Share

Electricity Market Share (Top 6 Suppliers)

Gas Customers & Market Share

Gas Market Share (Top 6 Suppliers)

Octopus Energy’s rise to the top was accelerated by its acquisition of customers from failed suppliers, most notably Bulb, as well as taking over Shell Energy’s domestic customer base. Meanwhile, British Gas, part of Centrica, remains the single largest supplier of gas to UK homes.

Profiles of the Main Suppliers

Each of the UK’s largest energy companies has a different history and corporate structure. Here’s a brief look at the six biggest names.

Octopus Energy Trustpilot: 4.8★★★★★★★★★★(893,160 reviews)

Founded in 2015, Octopus Energy is a British-owned company that has quickly become the UK’s largest domestic energy supplier. It is known for its technology-driven approach and strong focus on customer service, which has helped it attract millions of customers organically in addition to its high-profile acquisitions.

British Gas Trustpilot: 4.4★★★★★★★★★★(359,409 reviews)

As the UK’s oldest energy supplier, British Gas is a household name. It is part of the British-owned Centrica group and, despite being overtaken by Octopus in overall customer numbers, it continues to supply more gas to UK homes than any other company.

E.ON Next Trustpilot: 4.5★★★★★★★★★★(240,522 reviews)

E.ON Next is the UK arm of the major German energy firm E.ON. It became the UK’s third-largest supplier after absorbing the customer base of npower in 2021, consolidating its position as a major player in the market.

OVO Energy Trustpilot: 4.7★★★★★★★★★★(307,205 reviews)

Another British-founded company, OVO Energy was established in 2009. Its major expansion came in 2020 when it acquired the domestic energy business of SSE, transforming it into one of the country’s largest suppliers overnight.

EDF Energy Trustpilot: 4.8★★★★★★★★★★(264,594 reviews)

EDF Energy is owned by the French state-owned energy company, Électricité de France (EDF). It is a significant generator of electricity in the UK - particularly from nuclear power - as well as being the country’s fifth-largest domestic supplier.

ScottishPower Trustpilot: 4.4★★★★★★★★★★(212,931 reviews)

Based in Glasgow, ScottishPower serves homes across Great Britain. It has been owned by the Spanish utility giant Iberdrola since 2007 and is currently the sixth-largest supplier in the UK market.

How Do Suppliers Compare on Customer Service?

Price is important, but customer service can make a huge difference to your experience. A good indicator of customer satisfaction can be found on review platforms like Trustpilot. Whilst scores can change, they provide a useful snapshot of how customers rate their suppliers.

Supplier Trustpilot Rankings

What About Smaller Suppliers?

Beyond the big six, there are over ten other smaller, independent suppliers operating in the UK. These companies often compete by offering niche products - such as innovative smart tariffs or a specific focus on renewable energy - or by aiming to provide a more personal level of customer service. It can be worth including them in your comparison, as they may offer a competitive deal that suits your needs.

Choosing the Right Supplier for You

When it’s time to choose a new energy deal, it’s wise to look beyond the headline price. Different suppliers and tariffs suit different households, so consider the following factors:

• Customer service ratings: As the scores above show, there can be a big difference in rated satisfaction levels. Check recent reviews to see what current customers are saying.

• Tariff options: Are you looking for the security of a fixed-term deal, or the flexibility of a variable tariff? Some suppliers specialise in smart tariffs that can save you money if you can shift your energy use to off-peak times. For more information, read our guide, ‘Understanding Home Energy Prices: A Guide to Tariffs, Quotes and the Price Cap’.

• Green credentials: If sustainability is important to you, look into a supplier’s energy mix and their range of renewable tariffs. You can learn more in our ‘A Guide to Green Energy Tariffs’.

• Additional services: Some companies offer perks like boiler cover, smart home technology, or loyalty schemes that might add value for you.

Government Support Schemes

Eligible households can get help with their energy bills through government programmes. The main one is the Warm Home Discount Scheme, which provides a one-off £150 payment towards electricity bills for low-income households. For the 2026/27 winter, the scheme runs from October to March. For most people, the payment is automatic if you receive certain benefits on the qualifying date, which for this winter was 23 August 2026. Your supplier must be part of the scheme to be able to provide the discount.

Frequently Asked Questions

Is the ‘Big Six’ Still a Relevant Term?

Yes and no. The term is still widely used to refer to the largest suppliers, but the companies within that group have changed. For example, Octopus Energy is a relatively new company that is now the UK’s largest supplier, whilst others like SSE and npower have been acquired and no longer have a domestic supply brand.

Why Did My Bill Go Up if There’s a Price Cap?

The Ofgem price cap doesn’t limit your total bill - it limits the price suppliers can charge per unit of gas and electricity, and the daily standing charge. Your final bill is determined by how much energy you use. If the price cap level rises, or if your household’s energy consumption increases, your bills will go up.

Do I Have to Stay With a Supplier if I’m Unhappy With Their Service?

No. If you are on a standard variable tariff or your fixed-term contract is ending, you are free to switch suppliers at any time without paying an exit fee. This is one of the most effective ways to ensure you’re on a competitive deal with a company that values your custom. Our guide, ‘Switching Home Energy Supplier: A Step-by-Step Guide’, walks you through the process.

Find the Right Energy Deal for Your Home

Choosing an energy supplier involves balancing cost, customer service, and the type of tariff that best suits your lifestyle. While the market is dominated by a few large names, it’s always worth comparing a wide range of suppliers to find the best value. To see what deals are available for your home, you can compare energy tariffs with SwitchPal.