Regulator Ofgem may be to blame for soaring bills and profits in the energy sector, five former regulators have claimed.

In a submission to the 18-month study under way by the Competition and Markets Authority into the energy market at the request of Ofgem, the five - including five including Stephen Littlechild and Sir Callum McCarthy -suggest Ofgem may have weakened competition through poorly designed regulation imposed since 2008.

They also question the independence of the review, saying it was important that it should be seen to be independent of Ofgem".

The regulator blames lack of competition across the sector for inflated bills.