NFU organic committee chairman Oliver Dowding said: "It has clearly misunderstood the timescales farmers work to when they convert. I doubt it will be able to increase supply to those levels even if it sources abroad. Tesco needs to make a long-term commitment to UK farmers to make it worth their while to go through the two-year conversion period. It also needs to agree a fair price."
Simon Wright, founder of the Organic Consultancy said: "When Tesco announced its target, the organic market was growing at 55%. That has levelled off to 15%. So long as we continue to see double digit growth, they could be looking at £500m by 2005."
A Tesco spokesman said: "We are committed to our target. And we are growing the business into high value lines like beers wines and spirits. "