Legislation just introduced means 2.5% of all the petrol and diesel bought in the UK must come from biofuels. That's a government target. But even before it was enforced, the government signalled it's cooling on the whole idea of biofuels - amidst concerns that its production is contributing to the rising price of food, and isn't proving all that environmentally friendly. Chancellor Alistair Darling called for a review saying, "It would be a profound mistake if we get into a situation where we are growing corn that is essential for feeding people and converting it into fuel.", he said. So why is the government insisting on the use of biofuels in petrol? Jackie Long reports.