How the UK Electricity Market Has Shifted
The UK electricity market has shifted dramatically in recent years. Suppliers have collapsed, new players have risen, and the balance of power looks nothing like it did a decade ago. Thanks to data published by Elexon, the organisation that oversees electricity settlement in Great Britain, we can see exactly how each supplier's market share stacks up by both electricity volume and customer (MPAN) count.
What the UK Energy Market Looks Like Now
The original 'Big Six', British Gas, EDF, E.ON, npower, ScottishPower and SSE, once held over 99% of the domestic market. That's ancient history now. SSE sold its retail arm to OVO in 2020, npower was absorbed by E.ON Next in 2021, and Octopus Energy acquired Shell Energy's customers in late 2023.
Today's Big Six are Octopus Energy, British Gas, E.ON Next, OVO Energy, EDF, and ScottishPower, and together they hold around 91% of the domestic electricity market.
| Supplier | Electricity Share | Notable |
|---|---|---|
| Octopus Energy | ~24% | Largest since late 2023 |
| British Gas | ~20% | Largest gas supplier |
| E.ON Next | ~17% | Absorbed npower |
| OVO Energy | ~13% | Acquired SSE retail |
| EDF Energy | ~11% | Biggest zero-carbon generator |
| ScottishPower | ~8% | Owned by Iberdrola |
| All others combined | ~8 to 9% | 72+ business suppliers |
Source: Ofgem Retail Market Indicators & Elexon Gross Supplier Market Share Data, 2025.
The Octopus Effect
Octopus Energy is the standout story. Founded in 2016, it overtook British Gas in late 2023 and now supplies around 6.8 million households. Growth came through a mix of acquisitions, inheriting 1.7 million Bulb customers and 1.3 million Shell Energy customers, and genuine switching, with around 800,000 customers actively choosing to join in 2023 alone.
Elexon's quarterly MPAN data shows their meter point count climbing by hundreds of thousands each quarter, while most other major suppliers have held steady or declined slightly.
Where Did the Smaller Suppliers Go?
Between 2018 and 2025, 54 energy suppliers ceased trading, affecting over 6 million customers. The energy crisis of 2021 to 2022 was the catalyst, wholesale gas prices surged to more than 10 times pre-crisis levels, and many smaller suppliers simply couldn't survive.
2021 alone saw 28 suppliers collapse, with November being the worst single month (11 failures, 1.88 million customers affected). The market is now far more consolidated, though 72 business energy suppliers remain active, meaning there's still real competition for commercial contracts.
What This Means for Your Business
Bigger doesn't always mean cheaper. Octopus may be the largest supplier, but commercial pricing depends on your usage profile, meter type, and contract timing. The best deal for a school looks very different to the best deal for a warehouse.
Stability matters more than ever. After dozens of supplier failures, choosing a financially robust supplier is critical, especially for multi-year contracts. Elexon's volume and MPAN data helps identify which suppliers are growing and which are shrinking. Tools like Purely Insights can also help you monitor your own energy usage in real time.
Wholesale costs are easing. Prices fell through the latter half of 2025 as gas markets stabilised and renewable output grew. Business rates are coming down but remain above pre-2021 levels, so getting your renewal timing right can make a real difference.
How Purely Energy Can Help
At Purely Energy , we work with over 30 suppliers and use market data like this to find the best deal for your business, not just the biggest name. Whether you're coming up to renewal or want to check if your current contract is competitive, get in touch for a free, no-obligation quote.
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