Following British Gas, npower and Scottish Power's announcements last week that they are set to increase prices, the Prime Minister has pledged that energy firms will be forced to give customers the cheapest available tariff under new legislation.
"I can announce that we will be legislating so that energy companies have to give the lowest tariff to their customers," he told MPs during Prime Minister's Questions.
It is possible that some of the best deals on the market will disappear. We could lurch from a minefield of deals to virtually none at all.
Downing Street sources are adamant tomorrow's energy bills announcement will stick to David Cameron's promise of lower tariffs, but will it?
Ministers are poised to announce plans to decrease energy bills in a bid to get customers on the lowest tariffs available.