Just days before new legislation in the UK mandating their use, there is yet more trouble for biofuels.

Professor Bob Watson, one of the British government’s top chief scientific advisers has said it would be wrong to introduce compulsory quotas for the use of biofuels in petrol and diesel before their effects had been properly assessed.

“If one started to use biofuels … and in reality that policy led to an increase in greenhouse gases rather than a decrease, that would obviously be insane,” Watson said. “It would certainly be a perverse outcome.”

Under the Renewable Transport Fuels Obligation, all petrol and diesel must contain 2.5% of biofuels from April 1. This is designed to ensure that Britain complies with a 2003 EU directive that 5.75% of petrol and diesel come from renewable sources by 2010.

John Beddington, the government’s chief scientific adviser, has also attacked the fuel, saying there “are real problems with the unsustainability of biofuels,” adding that cutting down rainforest to grow the crops was “profoundly stupid”. Not mentioning turning food crops into fuel…