Lesley Davies, chair of the National Right to Fuel Campaign (NRFC), points out that these increased profits come at a time when "the numbers in fuel poverty, who need to spend more than ten per cent of their income on energy and who make choices between having the heating on or feeding their children, have increased from around one million in England in 2004 to 2.5 million in 2007".
Davies, in a letter to the Guardian newspaper, says that this increase has come about as a direct result of the "massive increase in energy prices".
"We believe the level of these profits cannot be justified," Davies writes.
"Energy prices may be falling, but they are not going down anywhere near as quickly as they rose, or by as much.
"The energy regulator's blind faith that competition is working is not shared by NRFC and others. Ofgem needs to do more than promote corporate social responsibility to give confidence that these companies are not exploiting vulnerable consumers."
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.