Washington provides a subsidy of $0.51 per gallon to ethanol blenders and imposes a tariff of $0.54 per gallon on imports.

In the European Union (EU), most countries exempt biofuels from some gas taxes and impose an average tariff equal to more than $0.70 per gallon of imported ethanol.

Historic levels

Robert Zoellick, president of the World Bank, said on Thursday that while people in developed nations complained about the high cost of fuel to run their cars, poor people in developing nations were struggling to feed themselves.

Global food crisis

Food riots have erupted in Haiti, Egypt, Cameroon, Ivory Coast, Senegal, Burkina Faso, Ethiopia, Indonesia, Madagascar, the Philippines and Haiti in the past month   In Pakistan and Thailand, army troops have been deployed to avoid food being seized from fields and warehouses   Prices in these countries for foodstuffs such as rice, wheat, sorghum and maize have doubled   Causes of crisis range from financial speculation on food commodities, desertification, population increases, China and India's economic growth and use of grains to make biofuels   Cost of funding projects enabling governments to tackle food crisis could be up to $1.7bn   However world cereal production in 2008 is projected to increase by 2.6 per cent to a record 2,164 million tonnes   Source: United Nations Food and Agricultural Organisation (FAO)

"In many developing countries, the poor spend up to 75 per cent of their income on food. When prices of basic foods rise, it hits hard", he said.

"In just two months, rice prices have skyrocketed to near historic levels, rising by around 75 per cent globally and more in some markets - with more to come."

Zoellick said the world needs to recognise that food price inflation is contributing to a growing emergency.

The UN World Food Programme has said it requires $500m just to fill immediate need.

The World Bank says food price inflation is not a short-term phenomenon but will likely persist through 2008 and 2009 before demand slackens due to high prices.

Most people in the world's wealthiest countries take food for granted.

Even the poorest fifth of households in the US spend only 16 per cent of their budget on food.

In contrast, Nigerian families spend 73 per cent of their budgets on eating, Vietnamese 65 per cent, while Indonesians allocate about 50 per cent.

Last year, the food import bill of developing countries rose by 25 per cent as food prices rose to levels not seen in a generation.

Food commodities

World financers have also contibuted to the food price problem.

Rising bread prices in Egypt have contributed to protests that led to several deaths [EPA]

Commodities have attracted investors looking for a safe haven from failing investments in the highly-leverage mortgage sector.