Business Secretary John Hutton is expected to formally announce the decision in a statement to MPs on Thursday.

The decision clears the way for Britain to embark on its first program of building nuclear power plants for more than a decade.

A quarter of U.K. generation capacity will go off line by 2015. The prime minister Gordon Brown argued for nuclear power to fill the shortfall to help meet targets for cutting carbon emissions and secure energy supplies. Nuclear power currently accounts for about a fifth of electricity output.

However the plans face opposition from environmental campaigners who say such a move will be expensive and dangerous. Greenpeace says atomic power will not meet the projected energy shortfall. They want more wind and wave power generation and a push to improve energy efficiency.

But Gordon Brown has said the decision is "a fundamental precondition of preparing Britain for the new world".

Nuclear operators say they could have new plants running by 2017.