It is not a repetition of the 2007-08 food crisis yet, but the current wheat rally – the fastest in almost 40 years – could soon transform into a full-blown price spiral, spilling over on to other crops such as corn and pushing up retail prices worldwide.

The 2007-08 crisis, the first in three decades, saw the cost of agricultural commodities surge to record highs and riots in countries from Haiti to Bangladesh. It pushed wheat prices to an all-time high of more than $13 a bushel in the US. Yesterday, wheat in Chicago traded at nearly $8 a bushel, after rallying by 80 per cent since mid-June.

Yet the world is currently in a better starting position. Farmers have stockpiled large amounts of grain in their barns after two years of bumper crops. In 2007-08, grain stocks had been depleted after a string of bad crops in countries from Canada to Australia.