It is not right that the Big Six energy suppliers own 99.9 per cent of the consumer market, Ed Miliband has argued.
The Labour leader said in his speech about responsibility amidst the phone hacking scandal that "we must take action to open up the market over the coming months".
He claimed it is not healthy for a democracy when there is too much power in one set of hands and said it is not good news for consumers either.
The opposition leader commented: "To ensure a more responsible country we need a culture which demands it, rules which enforce it, and to break up concentrations of power which undermine it."
Mr Miliband's remarks came after an Ofgem investigation found competition is stifled by confusing tariffs and a lack of transparency in the energy market.
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