The Prime Minister's official spokesman said Ofgem has given "a very strong signal" that energy companies will not "get away with" bad practice after the it fined ScottishPower £8.5 million.
Asked if David Cameron was happy with the level of the fine, he replied:
Those must be, of course, decisions for the regulator but I think it does send a strong signal in response to bad practice that was being looked at here.
More top news
Six people have begun living in a dome in Hawaii to simulate what life would be like on Mars.