Biofuels have forced global food prices up by 75 per cent - far more than previously estimated - according to a confidential World Bank report published in a British newspaper today.
The assessment is based on a detailed analysis by Don Mitchell, an internationally respected economist at the Washington-based global financial body, the Guardiansaid.
The figure contradicts US government estimates that plant-derived fuels have contributed less than 3 per cent to food-price increases, the newspaper said.
It will add to pressure on governments in Washington and Europe, which have turned to biofuels to reduce emissions of greenhouse gases and reduce their dependence on imported oil.
Leaders of the G8 leading industrial countries meet next week in Japan, where they will discuss the food crisis and come under intense lobbying from campaigners calling for a moratorium on the use of plant-derived fuels.
Rising food prices have pushed 100 million people worldwide below the poverty line, according to the World Bank, and have sparked riots from Bangladesh to Egypt.
US President George Bush has linked higher food prices to higher demand from India and China, but the World Bank study said: "Rapid income growth in developing countries has not led to large increases in global grain consumption and was not a major factor responsible for the large price increases."
Meanwhile the European Union may get barely one-third of its target for biofuels in transport fuels from home-produced sources by 2020, requiring massive imports to meet the goal, a draft European Environment Agency report said.
The EU plans to source 10 per cent of transport fuels from renewable sources by 2020, with the bulk of that seen coming from biofuels.
Critics say the target will contribute to deforestation in developing nations and soaring food prices.
The report, sent to the bloc's 27-member states for comments and seen by Reuters, shows the most cost-effective and sustainable scenario for biofuels would deliver just 3.4 percent of the EU's transport fuels from domestic production in 2020.
An EEA spokeswoman said the report was at an early stage and was not scheduled for publication until September.
She declined to discuss details but said the final figure may be higher as the model does not factor in the effect of soaring oil prices, international trade or the fact that biomass may be diverted from power or heat generation to boost its use in transport fuels.
An EU source said the 3.4 per cent figure could equally be reduced by ever tighter EU social and environmental standards.
"The rest of the 10 percent would either have to be imported or would not be acheived at all," added the source.