Derek Simpson, the general secretary of Amicus, and senior officials from the National Union of Mineworkers will urge Mr Brown to back a major investment in clean coal power stations to head off the threat of power cuts and rising electricity prices. Amicus is in talks to merge with the NUM.

Amicus said that at least six new coal-fired stations needed to be built to replace ones that will be forced to close down over the next few years because of environmental legislation from Brussels.

The union also wants the Government to commit to extending the lives of Britain's ageing nuclear reactors as they begin to reach retirement at the end of this decade.

The prospect of power cuts this winter has already been raised by MPs and one of the operators of Britain's biggest gas import terminal, Bacton, on the east coast. Amicus said there was a "real possibility" of blackouts from 2005 onwards as the new European directives begin to take effect.

The union is most worried about the new carbon emissions trading scheme, which will have the biggest impact on power stations.

But there is also a Brussels directive in the pipeline concerning sulphur emissions, which will force coal-fired stations to close unless they have expensive clean-up equipment fitted.

Mr Simpson said that a programme of publicly-funded research and development into clean coal technology needed to be undertaken as part of a wide-ranging review of the UK's energy requirements. He warned of "dire consequences" otherwise.

"We could be suffering routine blackouts in the next few years and the sort of energy hikes we have seen in recent weeks because of the increasing reliance on foreign supplies from unstable countries," the Amicus leader added.