Wheat pricing has almost tripled since the turn of the century, according to the World Bank.

The bank’s development prospects group’s lead economist Don Mitchell has warned that it is likely to take several years "for supplies to increase to rebuild stocks and allow prices to fall".

Grain price spikes, in combination with higher energy and fertiliser prices, plus increased demand for biofuels, have hit developing countries hardest. In Egypt, the army has been told to bake more government-subsidised bread to cover a shortfall. Four people have been killed in fights outside bakeries as a shortage of bread has led to violent confrontations between customers, with some accusing bakers of selling subsidised flour and bread on the black market.

United Nations agency the World Food Programme (WFP) has appealed for funding to close a $500 million gap, due to a global spike in food and fuel prices. If this is not found, the WFP will have to ration food aid to developing countries.