Energy regulator Ofgem has said that more than four million people – 750,000 more than in 2005 – switched their electricity or gas supplier last year in a bid to find cheaper utility bills.

Each person who switched cut their energy bill by an average of £150 and Ofgem said the trend was hitting the ex-monopoly suppliers, like British Gas, which saw its market share dip below 50% for the first time.

However, Ofgem also said that the number of people switching would probably dip in 2007 as wholesale prices came down and cheaper utility bills arrive on consumers’ doormats as a matter of course.

Alistair Buchanan, Ofgem chief executive, said: “Energy customers have given expensive suppliers the boot with over four million moving to a cheaper supplier in the first 10 months of 2006.”

He continued: “Our competitive energy markets have attracted over £10bn of investment in gas importation projects, enabling suppliers to better control the gas price, and these are beginning to take the heat out of wholesale gas prices.”

Ofgem also noted that British consumers are far more likely to move energy supplier than their continental counterparts. Less than 10% of German consumers have switched their energy supplier since 1998 and only one in seven French consumers have made the move to cheaper utility bills.