How Octopus became #1
In 2026 Octopus Energy is the UK's largest energy retailer — approximately 24% of both electricity and gas customers, narrowly ahead of British Gas. The company overtook British Gas in late 2023 following the completion of its acquisition of Shell Energy's UK domestic customer base. It has grown organically through high net-promoter scores, an in-house technology platform (Kraken) that it also licenses to other utilities globally, and an early lead on time-of-use and EV-aware tariffs.
Domestic tariffs
Octopus has the most diverse domestic tariff lineup of any major UK supplier. The headline products in 2026:
- Octopus Flexible — standard variable tariff, capped under the Ofgem cap. The default for new sign-ups.
- Octopus 12M Fixed — 12-month fixed deal, typically priced at or just below the cap.
- Octopus Tracker — daily wholesale-linked unit rate. Riskier but historically cheaper. Requires a smart meter.
- Octopus Agile — half-hourly unit rates published a day ahead. Best for households with shiftable load (EVs, batteries, large appliances).
- Octopus Go — five hours of cheap overnight electricity, designed for EV charging.
- Cosy Octopus — designed for heat pumps, with two cheap windows aligned to typical heat-pump operation.
For most households, Flexible or 12M Fixed are the right starting points. Tracker and Agile reward engagement but punish complacency.
Business proposition
Octopus for Business has grown rapidly and now competes seriously with British Gas Business and EDF for SME and mid-market clients. Strengths: clean digital onboarding, rapid quote turnaround, strong renewable credentials (Octopus is the UK's largest investor in onshore wind through its sister company Octopus Energy Generation). Weaknesses: less tailored half-hourly product set than the deepest specialist B2B suppliers (Crown Gas & Power, SmartestEnergy) and less established account management for portfolios of 50+ meters.
Customer service
Octopus has consistently topped UK consumer satisfaction surveys for energy suppliers since 2018. Citizens Advice ratings, Trustpilot scores and Which? satisfaction surveys all place Octopus comfortably in the top tier — typically 4.5–4.8 out of 5.
Their service philosophy — "no scripts, no call queues, real engineers, real names" — has been imitated but rarely matched. The main caveats: scale brings inevitable variability, and a small but consistent fraction of customers (typically inherited from acquisitions) report longer resolution times than the headline stats suggest.
When Octopus might not be right for you
- You want the cheapest fixed price, full stop. Octopus is rarely the absolute cheapest — typically 1–4% above the headline best-buy. They compete on service and product range, not bottom-line price.
- You have a complex business portfolio. For half-hourly multi-site portfolios with bespoke risk profiles, specialist B2B suppliers often win on price.
- You are on a Tracker or Agile tariff and stop paying attention. These products genuinely save money but require some engagement. If you don't want to think about energy, take a fix.
Verdict
Octopus is the UK's strongest all-round energy retailer in 2026: excellent service, real renewable credentials, a rich product range and price competitiveness within a few percent of the headline best-buys. For most domestic households, it's a safe and high-quality default. For business customers, it is now serious competition for the legacy Big Six — but always tender against the rest of the market before signing.