The Big Six energy firms are facing renewed criticism for poor levels of customer service.
A survey of more than 8,900 people by consumer group Which? found half of the six had below average satisfaction ratings while the other three were only just above average.
For the sixth year running Npower had the lowest customer satisfaction rating with 41 per cent, closely followed by Scottish Power with 44 per cent, while SSE, with 52 per cent, was just below the average of 53 per cent.
Eon with 53 per cent, British Gas with 54 per cent and EDF with 55 per cent were just above the average.
For the fifth year running, the best performers were smaller firms with OVO Energy on 82 per cent, followed by Good Energy with 81 per cent and Ecotricity with 77 per cent.
Despite the poor satisfaction ratings, 87 per cent said they were still supplied by one of the Big Six with just 10 per cent switching in the past year.
Which? executive director, Richard Lloyd, said: “Once again the smaller energy suppliers are leading the way.’