The annual customer satisfaction rankings from consumer group Which? have laid bare the stark divide in performance among the UK's major energy suppliers. The research, published in January 2026, crowns E (Gas and Electricity) as the nation's top provider, while highlighting serious shortcomings at several household names including Scottish Power, EDF, and British Gas.
The Champions and the Laggards
E (Gas and Electricity) emerged as the clear winner, securing an impressive overall score of 79% in the assessment. Nearly nine out of ten of its customers (86%) stated they would recommend the firm to others. The provider earned four-star ratings for its customer service, the ease of getting in touch, and the clarity of its billing statements.
In a distant second place was Octopus Energy, achieving a respectable score of 74%. They were followed by 100Green and Sainsbury’s Energy, which scored 72% and 71% respectively. Co-op Energy and Outfox Energy matched Sainsbury’s score but did not attain a minimum of three stars in every category surveyed.
The Bottom Performers Face Criticism
At the opposite end of the spectrum, three major suppliers received damning overall scores of less than 60%.
Scottish Power was ranked the worst energy firm in the UK, receiving the lowest overall score of just 56%. It performed particularly poorly in its handling of customer complaints, scoring fewer points than any other provider in this critical area.
EDF fared only slightly better, coming second to last with a score of 58%. Which? noted that a key factor in its low ranking was that its phone lines and customer service email accounts are not monitored for as long as those of other companies.
British Gas found itself third from the bottom, with an overall score of 59%. The research found that while the company offered a "good amount" of support to customers in need, it consistently struggled with resolving complaints and managing customer switches effectively.
Methodology and Industry Response
The authoritative rankings are based on a survey of almost 12,000 energy customers conducted during September and October, combined with an in-depth assessment of 17 firms' behind-the-scenes practices and policies.
Emily Seymour, Energy Editor at Which?, issued a stark warning to underperforming companies: "With fixed tariffs now reliably cheaper than the energy price cap, there is no need for customers to put up with poor value for money or shoddy customer service. Any suppliers falling short need to improve or their customers will vote with their feet."
In response to the findings, the named companies defended their records. A spokesperson for Centrica, owner of British Gas, pointed to a more than 20% annual reduction in complaints over the past two years and cited recognition from Uswitch and the UK Customer Satisfaction Index. EDF highlighted its excellent Trustpilot rating of 4.8 but acknowledged the need for improvement. Scottish Power contested the methodology, stating that the Citizens Advice scorecard is the "gold standard" and better reflects its service investments.
The message for consumers is clear. With cheaper fixed tariffs available, loyalty to a provider delivering poor service is no longer necessary. Which? urges unhappy customers to shop around and switch to a supplier that offers both competitive pricing and superior customer service.
