But now questions about the wider environmental damage caused by converting farmers' fields to grow crops for biofuels have prompted a major government rethink.
Gordon Brown, the Prime Minister, said yesterday that the UK would reconsider how far it was prepared to sign up to proposals for a tenfold increase in the use of biofuels by 2020, in response to fears this was causing a "world crisis" in the cost of food.
The doubling in price of rice and wheat has sparked riots in Egypt and Haiti, and led to a World Bank warning that 100 million people could be pushed deeper into poverty. And it emerged yesterday that price surges have seen grocery bills in the UK rise by around 15 a week in a year.
Since Tuesday of last week, 2.5 per cent of the petrol and diesel sold at the pumps in Britain has been bioethanol or biodiesel. Under European Union targets, this is due to increase to 5 per cent by 2010, and 10 per cent by 2020.
The UK's 5 per cent target is only half that on the Continent – and now Mr Brown has bowed to new scientific fears that biofuels may be doing more harm than good.
Total biofuel consumption in the UK is likely to be about 1.2 billion litres this year and 2.5 billion litres in 2010. Five years ago, it was only 19 million litres.
Yesterday, ahead of a Downing Street summit on the world food crisis, the Prime Minister said: "Now we know that biofuels, intended to promote energy independence and combat climate change, are frequently energy inefficient.
"We need to look closely at the impact on food prices and the environment of different production methods and to ensure we are more selective in our support.
"If the UK review shows that we need to change our approach, we will also push for change in EU biofuels targets."
Campaigners welcomed Mr Brown's prioritisation on feeding the world's hungry and recognising the environmental damage done in claiming virgin land for crop growth.
But enthusiasts for biofuels, such as the National Farmers' Union, say UK regulations mean all crops that are grown for fuel, such as oilseed rape, are sustainable – and have the added benefit of also being used as animal feed.
The government position will become clearer in June when a review will outline the "indirect effects" of biofuels.
But Friends of the Earth urged the Prime Minister to be bold and abandon the EU targets. Vicky Hird, its food campaigner, said: "Gordon Brown is right to be concerned about the impact of biofuels on food prices and the environment. Evidence is growing that they cause more harm than good. Food production must be revolutionised to prevent a global catastrophe.
"We must stop putting the profits of agri-business ahead of the welfare of millions of poor people around the world."
Norman Baker, the Liberal Democrats' transport spokesman, told The Scotsman: "It's quite clear the government has realised there is a problem.
"Biofuel isn't the answer. Biofuel, at best, was only ever a bridge. The answer, ultimately, is electric vehicles with renewable energy generation.
"Biofuels are displacing food production and, in some cases, the carbon consequences of biofuels are no better than the substances that they are replacing."
Garry Staunton, technology director at the Carbon Trust, said: "It's wrong at many levels to say we ought to grow crops to drive our cars, rather than to feed people. But for many years now, the planet has produced more food than it has consumed. Turning that surplus into fuel can now be achieved.
"But we are moving from converting surplus food into fuel, into a situation where there is direct competition."
Phil Bloomer, Oxfam's policy and campaigns director, said: "Setting mandatory targets for biofuels before we are aware of their full impact is madness. Not only are biofuels pushing up food prices, but they are also linked to human-rights abuses."
A Department for Transport spokeswoman said: "What the Prime Minister said wasn't about putting the brakes on biofuels. It was about making sure the biofuels we support in the UK are truly sustainable."
Global crisis sees staples rise by up to 130%
THE world food crisis has plunged dozens of countries into starvation and sparked riots across the globe.
The price of wheat has risen by 130 per cent in a year, and rice has shot up by 74 per cent. Millions of the world's poorest people are now facing starvation.
Gordon Brown, the Prime Minister, yesterday called for international action. Writing on the Downing Street website, he said: "The World Health Organisation views hunger as the No 1 threat to public health across the world, responsible for a third of child deaths. Tackling hunger is a moral challenge to each of us."
The UK government is to provide 30 million to help the 840 million people estimated to be suffering chronic hunger, while the UN Food and Agriculture Organisation says the food crisis has hit 36 countries.
Earlier this month, the World Bank announced emergency measures, including a doubling of loans to African farmers.
Economic growth has created a desire for more meat in China and India, so more corn is needed to feed livestock – again forcing the price up. Meanwhile, the soaring cost of oil has increased the price of food processing and transport. Added to this, climate change is resulting in floods and droughts that are destroying harvests. Last year, Australia suffered its worst drought for over a century.
Downing Street is hosting a meeting today involving scientists, supermarkets, farmers and aid agencies. Their aim is to come up with a plan that can be presented to the EU, G8 and UN.
Why the rush? Politics takes precedence as usual
A DESIRE to end dependence on dwindling stocks of oil from conflict zones has sparked the rush towards biofuels as much as environmental motives, according to experts.
Two years ago, George Bush, the US president, gave a State of the Union speech that declared the United States was "addicted to oil". He called for 75 per cent of imported oil to be replaced by 2025 by alternative sources of energy, including biofuels.
Professor Chris Rhodes, an environmental consultant, thinks Mr Bush was motivated by a desire to end the US's dependence on oil stocks from countries in the Middle East and other unstable areas.
Biofuels offered a way to sever the dependency and at the same time be seen to tackle climate change.
"However, if you grow crops for biofuel on land for food, you run out of land," Prof Rhodes said. "There's only so much arable land available."
Anthony Day, an author and climate-change expert, agrees and believes that in their rush towards biofuels, governments did not consider the consequences.
Struan Stevenson, a Scotland MEP, said: "It's clear now that the race towards biofuels has led to vast areas of rain forest being burned.
"We are destroying the air-conditioning system of the world."
UK shopping bills up by 800 in just a year
FOOD bills for the average family in Britain have risen by 800 in a year, as the highest rate of food inflation for a generation drives up supermarket prices, it emerged yesterday.
A basket of 24 common items such as teabags and pasta sauce costs 15 per cent more than it did 12 months ago, according to a survey.
The supermarket price survey found that six pints of semi-skimmed milk are now 28p dearer – a rise from 1.68 to 1.96 – at Tesco, Asda and Sainsbury's.
The cost of a thick white loaf has gone up by more than 20 per cent, from 54p to 65p, at both Tesco and Asda.
Customers are paying nearly 50 per cent more for a dozen medium free-range eggs at the top three supermarkets, according to MySupermarket.co.uk – from 1.75 to 2.58.
A packet of fusilli pasta at all three has nearly doubled from 37p to 67p, the survey found.
Also in the basket of goods were cheese, potatoes, bolognese sauce and cornflakes.
The figures show inflation is costing a family spending around 100 a week on groceries an extra 15 a week, or 780 more over a year, reports said.
Demand for basic agricultural goods has led to huge increases in global grain prices in recent months. Those costs then pass on down the "food chain" to meat and dairy products as farmers pay more to feed livestock.
Johnny Stern, managing director of MySupermarket.co.uk, said: "The conclusion is that supermarkets are passing on a sizeable amount of the increased costs. The average customer cares about the products they need to put in their basket every week that they don't have any choice about."
John Bason, finance director of Associated British Foods, one of Britain's biggest food producers, said that wheat prices had doubled in a year and supermarkets would have to raise the price of bread again.
The figures are likely to increase pressure on the ministers over the government's official inflation level. Critics say that it fails to reflect the pain felt by shoppers.
Consumers are also being hit by rises in world oil prices. On Wall Street yesterday, crude prices hit record highs.
Higher food and fuel prices mean the Bank of England has less room to manoeuvre when it comes to cutting interest rates, say analysts.
Vince Cable, the Liberal Democrats' Treasury spokesman, said: "Rising food bills will hit families already struggling to keep their heads above water following big rises to many utility bills.
"The government must show more urgency in ensuring the current world talks on agricultural trade no longer drift hopelessly because of a lack of political will," he said.