The United Nations' Food and Agriculture Organisation estimates biofuels have contributed to about 10 per cent of the current food price rise. It argues that the surge of oil prices - through costlier fertiliser and diesel - is having a greater impact on food prices.

Jeff Tschirley, the chairman of the Inter-Departmental Working Group on Bioenergy at FAO in Rome, said: "Biofuel has been made a culprit, but we don't see it as the major [factor] responsible for high food prices."