Power struggle: Which? reveals the best and worst suppliers as switching returns to the energy market

E (Gas & Electricity), Octopus Energy, 100Green and Sainsbury's Energy have been crowned as Which? Recommended Providers in the consumer champion's annual energy firm rankings, as some of the biggest providers - including Scottish Power, EDF and British Gas - languish at the bottom of the rankings.

From September to October 2025, Which? surveyed almost 12,000 energy customers for its annual customer satisfaction survey. The consumer champion also carried out an in-depth assessment of 17 energy firms' behind-the-scenes practices and policies to find out which energy firms are falling short and which are outshining the competition.

Scottish Power, EDF and British Gas finished at the bottom of the table - with overall scores of less than 60 per cent. All three companies received two star ratings across the board in Which? customer survey. 

Scottish Power received the lowest overall score of 56 per cent. It fared poorly in the consumer champion's background assessment too - receiving fewer points than any other provider when it came to its complaints handling, and middle-of-the-road scores in most other areas.

EDF came second last, with an overall score of 58 per cent. EDF received the 

the lowest score in Which?'s assessment when it came to contacting the supplier, largely because its phone lines and customer service email accounts are not monitored for as long as other providers.

British Gas came third from the bottom with an overall score of 59 per cent. Its performance in Which?'s background assessment was a mixed bag. It offers a good amount of support to those who need it, and scored highly when it came to contacting the supplier, but struggled to resolve complaints in a reasonable timeframe and did not get a single point for its switching service.

At the other end of the scale, four providers outshone the competition and were crowned Which? Recommended providers - E (Gas & Electricity), Octopus, 100Green and Sainsbury's Energy.

E (Gas & Electricity) received the highest overall score of 79 per cent and was named a Which? Recommended Provider (WRP) for the second time. 

E (Gas & Electricity) received four stars in Which?'s customer survey for customer service, ease of contacting and clarity of its statements. Nearly nine in 10 (86%) E customers said they would recommend the provider. 

It also got the highest score of any provider in Which?'s behind-the-scenes assessment, performing particularly well for its complaints handling, its smart meters and switching performance. 

Octopus Energy came second in Which? rankings - with an overall score of 74 per cent - and was named a WRP for the ninth year running. It is the only big supplier to be awarded a WRP.  It received a mix of three and four-star ratings in Which?'s customer survey and scored maximum points for supporting customers who need it in the consumer champion's behind-the scenes assessment. 

100Green and Sainsbury's Energy were also named WRPs with overall scores of 72 and 71 per cent respectively. 

100Green is a small supplier but has established a reputation for solid customer service. This is the second year in a row that the provider has been made a WRP. It received the highest score in the customer survey and performed well in some of the behind-the-scenes assessments, and 94 per cent of its customers said that they would recommend the provider. 

Sainsbury's Energy qualified as a WRP for the first time. It achieved four stars for customer service in the customer survey, clear statements and ease of getting in touch. It also performed well in the background assessment, especially when it came to smart meter targets and providing help for customers who need it.

Although Co-op Energy and Outfox Energy received the same overall score as Sainsbury's Energy, they were not named WRPs as WRPs must score three stars or higher in every category of the customer survey. 

Over the last year, more fixed deals have returned to the market as energy prices have stabilised and they are now reliably cheaper than the price capped standard variable tariff. With switching returning to the market, there is no need for energy customers to put up with sub-par service or bad value for money. 

Which?'s survey found that nearly half (45%) of those who actively chose their supplier did so because their new provider offers a lower price than what they have been paying and a third (33%) said they chose their supplier because of their good reputation. 

Eight in ten (81%) who chose their supplier and have been a customer for up to two years said the process was easy. 

Emily Seymour, Which? Energy Editor, said: 

“Our research shows that while four suppliers are outshining the competition, some big firms - including Scottish Power, EDF and British Gas - are letting their customers down. 

“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. 

“Anyone who is unhappy with their provider should shop around and move to a supplier with a cheaper fixed tariff and better customer service.”

-ENDS- 

Notes to editors:

Advice for consumers looking for fixed deals

Over the last year, more fixed deals have returned to the market and options are consistently available at rates cheaper than the price capped standard variable tariff. People can compare energy deals here.

As a rule of thumb, Which? would recommend looking for deals cheaper than the price cap, not longer than 12 months and without significant exit fees.

From 1 April 2026, certain energy policy costs relating to funding for the Energy Company Obligation (ECO) and Renewables Obligation (RO) schemes will be removed from the energy price cap. The government has confirmed that it expects energy companies to pass this saving on to customers on fixed tariffs as well.

It's also important to consider the customer service of the firm you're switching to and how quickly and efficiently they'll be able to resolve any issues.

Research

Which? surveyed 11,985 GB adults, who are at least jointly responsible for their energy bills, between September and October 2025. Fieldwork was carried out online by Deltapoll. 

Which? Recommended Providers (WRP) must achieve 70% customer score, all survey star ratings three stars or above and score above average in the Which? Assessment to qualify. 

Customer score is based on satisfaction and likelihood to recommend the brand. Customers rated other service aspects, shown as star ratings. We require 50+ responses to give a rating. The number of respondents for each firm are shown in brackets.

The Which? assessment score is based on a supplier questionnaire - as well as publicly available information and Which? research - covering five key areas: the company's track record on receiving and resolving complaints, what support is available for customers who need it, the provider's customer contact channels and their monitored hours, how well the company is doing against smart meter targets and smart meter operating performance and how the company handles the switching process. The score is weighted as; complaints performance (30%), supporting customers who need it (25%), contacting your supplier (25%), switching (10%) and smart meters (10%). 

The overall score is an equal combination of customer score and Which? assessment score.