Consumers have been stung by the rising cost of energy

Cutting their annual bills by around �150, the number of people changing their energy provider in 2006 was 750,000 higher than in 2005.

Ofgem said the growing trend was hitting the former monopoly suppliers, such as British Gas, whose market share had gone below 50% for the first time.

The regulator said it expected bills to fall in 2007 as wholesale prices dip.

It said it wanted to see suppliers pass on these expected reductions to customers.

'Competitive market'

"Energy customers have given expensive suppliers the boot with over four million moving to a cheaper supplier in the first ten months of 2006," said Ofgem chief executive Alistair Buchanan.

"Our competitive energy markets have attracted over �10bn of investment in gas importation projects which are now beginning to take the heat out of wholesale gas prices.

"While British Gas has already indicated that they will be cutting prices this year, Ofgem will be watching all energy suppliers to make sure they compete as wholesale prices fall as hard as they did when prices rose."

Britons are far more likely to up-sticks from their energy suppliers than their continental counterparts.