In its findings from a seven-month probe into the energy supply market, Ofgem was particularly concerned to see behavior by supply companies that was affecting 4.3 million customers without gas supply and no access to the most competitive offers.

At the same time, the regulator has conceded that competition is generating a wide range of tariffs and products. Ofgem said that there is strong consumer awareness of, and satisfaction with, switching. The regulator also found no evidence of an energy supply market cartel.

Ofgem’s report builds on the regulator’s commitment to help vulnerable customers through initiatives such as the Fuel Poverty Action Program and Ofgem’s Consumer First program.

Alistair Buchanan, CEO of Ofgem, said: These are hard times and we are taking a hard line on behalf of disadvantaged consumers. We accept that global influences are pushing up costs but the suppliers must change their behavior and cement consumer confidence. If they fail to satisfy our requirements voluntarily then we can move to a Competition Commission reference.