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Ofgem questions energy prices of "big six" companies

10 June 2014 Last updated at 21:31 BST

Energy suppliers risk "undermining public confidence" in the market by failing to respond to falling wholesale prices, the regulator has said.

Dermot Nolan, Chief Executive of Ofgem said the "big six" gas and electricity companies should explain to customers why falling wholesale prices have not been passed on to household bills.