The UK's biggest coal-fired power plant is to be the subject of a £100m project aimed at cutting carbon emissions.

The owner of Selby Power Station, Drax, said it intended to revamp turbines at the North Yorkshire site, in a bid to improve efficiency by five per cent and save a million tonnes of coal.

The five-year strategy is expected to take place between 2008 and 2011, and the firm said it was in the final stages of negotiations over the preferred supplier.

Drax is the UK's fourth most polluting power station per unit of electricity produced, according to the WWF's Dirty Thirty report published last year.

Environmentalists targeted the company in the summer, claiming it was the "single largest emitter of carbon dioxide in the UK" and demanded it reduce emissions.

But yesterday Drax, which produces seven per cent of the country's electricity needs, said the turbine changes will be the equivalent of taking 275,000 cars off the road.

Drax was responsible for 21 million tonnes of CO2 carbon emissions in 2005 and said the work would cut that figure by one million tonnes a year.