Gordon Brown has called for a forum of supermarkets, the British Retail Consortium and other groups to investigate how to eliminate plastic bag wastage.

Some 13 billion single-use plastic bags are distributed each year, which equates to 10 per household a week. Retailers including Asda, Saisbury's, Tesco and Boots have already set up a voluntary initiative to reduce the use of plastic bags by 25 per cent by the end of next year.

The Prime Minister told the WWF charity in London, ahead of a conference on climate change in Bali, that rich countries such as the US and the UK must raise their carbon reduction targets from 60 per cent to 80 per cent.