Green labels for shoppers

Just as food carries warnings on salt, sugar and fat, the new labels would carry a sign or figure to alert shoppers to the CO2 emissions used.

The label could be based on a "traffic light" system that would show red for highly wasteful products and green for those with lowest impact on the planet. The scheme, which will be the first in the world, was unveiled by climate change minister Ian Pearson.

Tesco, B&Q, Marks & Spencer and BT will work with green experts and academics to decide how to measure emissions in the "whole life cycle" of a product from its manufacture to packaging, distribution and disposal.

The Carbon Trust, a company which advises business on how to cut emissions, and the Department for the Environment, Food and Rural Affairs will devise the new labelling system with BSI British Standards.

The scheme could throw up some surprises. Carnations grown under the sun in Africa in winter and flown here are likely to have a lower carbon footprint than those grown in Britain in heated greenhouses.

And despite their gas-guzzling, some 4x4s have a lower overall CO2 impact than smaller cars because of more efficient manufacturing techniques and because their parts can be recycled.

DVD players and TVs will get worse ratings if they include "stand by" modes, while products with excess plastic packaging that cannot be recycled will also be marked down.

Big retailers such as Tesco are keen to use the labelling to meet shoppers' demands for a simple way of measuring how green their products are.

Mr Pearson said: "The products that businesses make, buy and sell have an impact, both on climate change and the wider environment, at all stages from raw material to when the product is no longer required.

"More and more, businesses are looking for ways to reduce their impact on the environment. To help them achieve that we need a reliable, consistent way to measure these impacts that businesses recognise, trust and understand."