It is the responsibility of the Big Six energy suppliers to demonstrate they are offering the best deals on gas and electricity in order to rebuild the trust of consumers.
This is according to chief executive of Scottish and Southern Energy (SSE) Ian Marchant, who said in a letter sent to energy secretary Chris Huhne that it is important energy suppliers offer simplicity, transparency and a high level of customer service.
He added: "It is no longer acceptable for energy companies to offer significantly discounted products at the expense of one group of customers."
Mr Marchant stated large price differentials between customers who arrange their gas and electricity deals online and offline cannot be justified on cost grounds alone and may be in breach of Ofgem's rules.
Therefore, SSE is ending any difference in price between internet-only and other tariffs.
Mr Marchant's letter comes as npower were fined £2 million by the energy regulator for poor handling of customer complaints.
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