Biofuels could do more harm to the environment than good, Defra's chief scientist Professor Robert Watson has warned.

From 1 April, all petrol and diesel must contain 2.5% biofuel, however Professor Watson said this should be postponed until a review into the sustainability of biofuels was carried out.

“It would obviously be totally insane if we had a policy to try to reduce greenhouse gas emissions that's actually leading to an increase in the greenhouse gases from biofuels,” he warned.