Ben Garside, International Institute for Environment & Development 

The UK's biggest supermarket first announced its intention to put carbon counts on up to 70,000 products some 15 months ago. They will start to roll this out across Tesco own brand products very shortly.

Tesco states it has been working with the Carbon Trust to find an accurate method of labelling. "It has not been simple, but we are there," said CEO of Tesco Terry Leahy on 15th April. Tesco will unveil the details of the scheme shortly, and the chief executive said he hoped the labels "will end up being a standard".

This may however be a premature rush for first advantage in an increasingly competitive push for green credentials by retailers. The public consultation led by the Carbon Trust and the British Standards Institute (BSI) on an agreed set of methodologies to measure how much carbon is actual in our food - from seed to plate - is not yet in its final form. The BSI standard is not due in its final form until June and even with the standard in place, there is much work left to do in implementing it and in gathering the data needed - throughout what is a very complex set of supply chains.

Another contentious issue is that the BSI standard does not address the issue of labelling at shelf level - something that Tesco is very keen to move forward with. Some other retailers state that shelf-level labelling will add to consumer confusion, preferring to work behind the scenes with suppliers to reduce 'carbon hotspots' in the supply chain on the consumers' behalf.

What is certain about the Tesco launch, whether premature or not, is that it will raise consumer awareness of carbon issues and will also help to dispel the food miles fallacy that "local" is always best for the environment.