Now a secret World Bank report has been leaked that drastically re-asses the effect the fad of turning food into fuel has had on global food prices.
Biofuels have forced global food prices up by 75% - far more than previously estimated - according to a confidential World Bank report obtained by the Guardian.
The damning unpublished assessment is based on the most detailed analysis of the crisis so far, carried out by an internationally-respected economist at global financial body.
The figure emphatically contradicts the US government's claims that plant-derived fuels contribute less than 3% to food-price rises. It will add to pressure on governments in Washington and across Europe, which have turned to plant-derived fuels to reduce emissions of greenhouse gases and reduce their dependence on imported oil. Senior development sources believe the report, completed in April, has not been published to avoid embarrassing President George Bush.
"It is clear that some biofuels have huge impacts on food prices," said Dr David King, the government's former chief scientific adviser, last night. "All we are doing by supporting these is subsidising higher food prices, while doing nothing to tackle climate change."