"The taxpayer is still exposed," Mr Leigh commented, before adding that the government should "do a lot better job in monitoring the performance of the company, influencing its commercial strategy and ensuring that the eventual liabilities are as small as possible".
"Upon privatisation in 1996, British Energy took on full responsibility for its nuclear power stations, including the associated nuclear liabilities," he said.
"In actual fact, from 2002 when the company was restructured, those liabilities - uncertain in size but valued at £5.3 billion in 2006 - have been underwritten by the taxpayer."
The privately-owned company announced in 2002 that it could not afford the cost of shutting down old nuclear power plants and safely disposing of the waste.
A recently-published report claimed that the company had little incentive to reduce its liabilities by being more efficient - and it said that these liabilities are probably going to get bigger as a result of this.
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