The Big Six energy firms have come bottom of a new poll on customer satisfaction, with Npower voted the worst provider for the third year running.
The annual energy company survey run by consumer rights group Which? indicates that the UK's major energy suppliers are failing to meet customers' needs, while smaller firms are performing better.
The top spot was shared by independent suppliers Ecotricity and Good Energy, with both receiving a customer satisfaction score of 82%.
The six largest companies in the UK took all six bottom spots. Npower scored the worst, with a customer satisfaction score of just 31%, followed by British Gas (39%), SSE (41%), Scottish Power (41%), EDF Energy (44%) and Eon (45%).
British Gas and Npower were both below the average score of 41%, which has dropped from 49% last year and is the lowest average score for any consumer satisfaction survey conducted by Which? across any sector.
Which? executive director Richard Lloyd said: "Once again the biggest energy companies have been beaten by the smaller suppliers but there are no winners in a broken market that consistently fails consumers.
"Our findings highlight why it's vital that Ofgem's first Annual Review of competition clearly identifies why the market is failing and what needs to change. We want to see radical solutions to improve competition and keep prices in check, like the biggest energy companies being forced to separate wholesale generation from the retail arms of their business."
Ecotricity founder Dale Vince said: "People tend to switch energy supplier for three reasons: for a better price, a greener outcome or better customer service. "Our mission at Ecotricity is to provide all three and treat people how we would want to be treated ourselves.
"Big energy companies provide poor customer service. We've all been there, wading through the endless phone menus, queues and scripted conversations. At Ecotricity we think people deserve better"
Last week, Npower topped a list of most complained about firms, with a 25% rise in the number of unhappy customers. Between July and September, 253.1 complaints about Npower were made for every 100,000 customers - around eight times more than the best-performing Big Six energy supplier, according to Consumer Futures.