While the industry has broadly welcomed the Defra announcement, concerns have been expressed about how cost prohibitive a

carbon labelling scheme would be.

Speaking at the Climate Change and the Food Industry conference in London this week, Ellen Gladders, Tesco's climate change project manager, said the cost and time

line of a life-cycle assessment, from which

the carbon impact of a product is calculated, was not just a problem for SMEs but for large companies as well.

"We sell 70,000 products and half of those are own-label, which is a huge number and it requires an army of consultants to do it," she said. "So everyone is keen to establish a methodology that is accessible to large and small companies and is also workable."