British Energy has confirmed it is in advanced talks with an unnamed party after speculation in the media pushed shares up 6.27 per cent in afternoon trading.
Shares in the nuclear power station operator have risen since the BBC claimed this morning that British Energy is in advanced talks with a bidder.
In a statement to the stock exchange, the company said: "The board of British Energy notes the recent speculation about the status of its talks with third parties.
"The board confirms that it is in advanced discussions with one party. However, there can be no certainty that the discussions will lead to an offer being made for British Energy."
The BBC said French energy firm EDF and British Gas owner Centrica have bought British Energy and will probably announce early next week they are paying more than £12 billion for the company.
British Energy, which owns and operates eight nuclear power stations in the UK, has been up for auction for several months after the government said it intended to sell its 35 per cent stake in the firm.
The government is keen to replace the country's ageing nuclear reactors, in order to avert a future energy crisis.
A deal could raise up to £4 billion for the chancellor.