The price of wheat has risen this year for the same -reasons it did in the days of the pharaohs: the weather and the harvest. But there is a new source of demand for agricultural commodities that in the not too distant future - perhaps from the year after next - is likely to start putting upward pressure on prices.

Brussels and European Union member states have made commitments to steep increases in the use of biofuels for road transport. That is creating new markets for ethanol, which can be added to petrol and is produced from crops such as wheat and sugar, and biodiesel, which can be added to ordinary diesel and is derived principally from vegetable oils such as rapeseed and palm oil.