A group of big companies, including B&Q, John Lewis and Tesco, has written to Prime Minister Gordon Brown urging more action on climate change.

The letter, which was also sent to the leaders of the opposition parties, argues that the UK should work on the assumption that carbon emissions should be reduced by 30 per cent by 2020. At present, a reduction of 20 per cent is being targeted by the Government.

The business leaders also said that public procurement expenditure should be made in a more environmentally way in order to bolster the market for ecologically sound products.