According to energywatch, gas bills increased by 90 per cent and electricity bills by over 60 per cent in the three years to 2006. Rising wholesale prices were the main factor behind the increases - and since 2006, these have fallen by 50 per cent.
But retail prices dropped by just 15 per cent over the same period, says the consumer group.
"UK consumers continue to pay among the highest prices despite us having what is supposed to be the most competitive market," Allan Asher, energywatch's chief executive, said.
"Price cuts so far have not reflected the savings that suppliers have enjoyed over the last year and I call on suppliers to cut their bills."
A recent report from Oil and Gas UK showed that the UK's big businesses are paying more for their gas than anyone else in Europe.
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