The rising price of grains, on the back of soaring demand for biofuels, is putting pressure on aid agencies as they struggle to find enough food to feed the world’s poor.

“With 90m people to feed every year, we are concerned with any development that impacts on the price and availability of food,” said a spokesman for the United Nations World Food Programme, which last year sourced about 4m tonnes of food at a cost of around £300m.

In the past, most of the WFP’s resources have been in the form of surplus grain and other commodities from the EU and the USA. But now about half is in the form of cash and, as the price of commodities rises, so the amount of food this can buy diminishes.

There is a potential upside, however. “Given that almost all the people we feed are farmers, in the longer term they may well stand to benefit from greater demand for the commodities that they grow,” said the spokesman. “We can help by procurring more and more from developing countries. This helps stimulate the market in these countries and is good news for farmers.”