Britain's best and worst energy suppliers ranked

Scottish Power, EDF and British Gas have been named the worst energy suppliers in an annual ranking by Which? With just a 56% rating, Scottish Power received the lowest overall score and was awarded fewer points than any other provider for handling complaints.

Find tips and personal finances news in the Money blog EDF was marked down for not monitoring its phone lines and customer service email accounts for as long as other providers. And British Gas struggled with resolving complaints and switching customers.

At the other end of the table was E (Gas and Electricity), praised for its customer service, ease of contact and clarity. Octopus, Sainsbury's Energy and 100Green were the only other recommended providers this year.

"Some big firms - including Scottish Power, EDF and British Gas - are letting their customers down," says Which? energy editor Emily Seymour. "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." Sky News has contacted Centrica (which owns British Gas), EDF and Scottish Power for comment.

Centrica told Which? that complaints have fallen more than 20% each year for the past two and highlighted its dedicated line for vulnerable customers. An EDF spokeswoman said it was "committed to continuing to improve the service we provide to our customers".

It pointed to a Trustpilot rating of 4.8, adding: "We are focused on building on these strengths and continuing our efforts to deliver improvements." A Scottish Power spokeswoman said: "The independent Citizens Advice scorecard is the customer service gold standard with a much more robust and transparent methodology used to assess firms' performance. "It shows sustained, high-quality delivery for our customers, reflecting the huge investments we've made improving and enhancing our service.".