An energy firm's bid to restore trust with its customers may not result in cheaper electricity bills, its chief executive has admitted.
Scottish & Southern Energy (SSE) is to auction all its power on the open market by early next year - starting with a phased introduction this Friday.
The move will potentially satisfy a key concern about a lack of competition in the sector, by opening the sale of wholesale energy to any household supplier.
But in an interview for Sky's Jeff Randall Live, SSE boss Ian Marchant told Anna Jones there could be no guarantee of cheaper bills - following the latest inflation-busting increases this summer.
He said: "I believe it will create an environment in which we get the right prices for energy...there is a lack of confidence that those prices are incorrect."
Mr Marchant admitted the industry had lost public confidence.
Ofgem, the energy watchdog, had recently proposed forcing the main companies to sell up to 20% of their energy to help break their monopoly.
Smaller firms such as Co-operative Energy and First Utility have been struggling to gain market share.
This is in part due to the fact that little surplus energy created by the 'big six' currently makes the wholesale market.
What surplus there is is usually sold off in large chunks - unsuitable for smaller players.
At the Liberal Democrat conference last month, the Energy Secretary Chris Huhne had pledged to boost competition and urged consumers to 'shop around' for the best deals, suggesting many people were too lazy to help bring down their own bills.
SSE says its decision is aimed at restoring customer trust and it expects "one or two" from either Centrica (British Gas), nPower, E.ON, EDF Energy and Scottish Power, to follow suit by Christmas.
However, there is concern the move will have a limited impact on household bills because other companies still face the same high costs as a result of meeting Government environmental measures and price volatility.
Prices have been rising steadily as a result of increased wholesale costs and the major players have been severely criticised for soaring profits.
The 'big six' deny consumer groups' claims of profiteering.
They argue their earnings are justified as they aid crucial investment, demanded by the regulator and Government, in alternative energy.
Director of External affairs at Consumer Focus, Adam Scorer, said: "There have been many questions about how competitive the energy market is and the barriers to new energy suppliers.
"It is good to see one of the big players taking steps that will help smaller suppliers compete."
He continued: "It is unlikely to make much difference to prices across the big suppliers in the short-term, as they purchase most of their energy well in advance.
"But it should make it easier for new players to enter the energy supply business and help existing small suppliers to grow."
On the prospect of lower bills he also told Sky News: "More open trading will help to increase transparency over the prices suppliers pay and increase competitive pressure in the market - which will help to keep pricing fair for consumers."