Drivers filling up at the petrol pump may be unaware of it, but a rising proportion of their fuel is likely to have started life as a plant.

From Tuesday, vehicle fuel suppliers must ensure that 2.5 per cent of the product they sell is biofuel – ethanol, made mostly from distilled grains, or diesel made from plants such as oilseed rape or soya. This will rise to 3.75 per cent by 2009 and 5 per cent by 2010.