Plans for Britain�s future nuclear supply emerged in sharp focus yesterday after the French power giant EDF unveiled a £12.5bn deal to buy British Energy and build four new reactors in the UK.

Plans for Britain's future nuclear supply emerged in sharp focus yesterday after the French power giant EDF unveiled a £12.5bn deal to buy British Energy and build four new reactors in the UK.

The state-owned company, already one of the UK's top six energy suppliers, plans to take over British Energy's eight nuclear generators, including Hunterston B and Torness in Scotland, and has identified six potential sites for its new model of water-pressurised reactor south of the border.

The deal was welcomed as a "significant step towards the construction of a new generation of nuclear stations" by Gordon Brown. It was also applauded by Alex Salmond - who received assurances from EDF in June that it would retain British Energy's offices in East Kilbride, currently its headquarters - despite the Scottish Government's insistence that no new nuclear power stations would be built here.

Consumer groups and industry analysts reacted cautiously, however, warning that the deal meant further consolidation in the energy sector and could lead to rising bills.

There were also fears from proponents of nuclear energy about the shape of Scotland's future energy mix, which will be left without any nuclear element after its two existing reactors are decommissioned in 2016 and 2023.

The deal will net the UK Government more than £4bn for its 36% stake in British Energy.

EDF - majority-owned by the French government and the world's biggest nuclear provider - said it planned to "maximise the potential" of British Energy's existing eight sites and hoped to build four new reactors using new technology.

Construction of the new reactors is due to start in 2012 and the first could be up and running by 2017.

The group is also in talks to sell a 25% stake in the new British Energy to Scottish Gas parent firm Centrica, which wants to secure a power-sharing arrangement once the takeover is complete.

The deal, one of the largest ever direct foreign investments in Britain, will see EDF pay 774p a share - 9p higher than the price offered in July, which was rejected as too low by major British Energy shareholders.

The UK has 10 nuclear power stations, eight owned by British Energy and two by the Nuclear Decommissioning Authority (NDA), with decommissioning dates from this year to 2035.

In its announcement yesterday, EDF said the UK Government had planned for two or three further reactors to be built by a rival company. EDF and the NDA have agreed to sell land to other potential operators for possible new builds, with a raft of rivals interested.

But while sources in British Energy have previously said there was potential for a new-build reactor at Torness, in East Lothian, or Hunterston in Ayrshire, both options appear to have been ruled out in yesterday's deal.

Brian Wilson, former Labour energy minister, last night claimed Scotland was in danger of becoming a net importer of energy and raised doubts as to the long-term future of the East Kilbride base. "Scotland will pay a heavy price for Alex Salmond's prejudice (against nuclear power)," he said.

"The rest of the world has woken up to the fact that nuclear is an essential part of the low-carbon mix. We're still in a timewarp in which that has passed the SNP by."

His concerns were echoed by Liz Cameron, chief executive of Scottish Chambers of Commerce.

"We would agree wholeheartedly with the Scottish Government's aim of Scotland being the lead in terms of renewable energy," she said. "However, we need a reality check in that we do not currently have the capacity."

Labour's finance spokesman Andy Kerr said that, while the EDF takeover raised concerns over jobs and HQ functions, it was also an opportunity to secure technical skills in Scotland.