The environmental body has developed a methodology to calculate the amount of carbon produced by consumer goods from creation to sale and will provide a Fairtrade-style label for products that submit to a carbon-audit.

Companies participating in the pilot scheme in Britain can use the label on their goods to display a product's carbon impact from source to store. However, brands that don't reduce their footprint with two years will lose the eco-mark.

The Carbon Trust analysis showed that one 34.5g bag of Walkers' crisps was responsible for 75g of carbon emissions.

Separate pilot carbon audits for Innocent smoothies and Boots' organic ingredients shampoo range found the majority of carbon emissions come from the cultivation of agricultural raw materials. In the case of Walkers, energy was expended by farmers deliberately storing their potatoes in humidified warehouses to add moisture and, therefore, extra mass to shipments, which Walkers pays for by weight.

The crisp company was in turn expending expense and energy in the extra amount of frying time necessary to transform wet spuds into dry snacks. The carbon audit highlighted this hitherto unknown inefficiency, the company said.

Walkers also said the audit helped it to save �225,000 ( 369,000) on its supply chain process as well to refocus activities to save 2,000 tonnes of CO2 per year.

The Carbon Trust . . . a private company funded by British government departments, the Scottish Executive, the Welsh Assembly Government and Invest Northern Ireland . . . claims carbon labelling can also competitively enhance the attraction of a product to an increasingly eco-conscious public.