Gordon Brown called for prudence in the kitchen last night, telling us not to throw away so much food.

With prices soaring, he suggested we could save up to £8 a week by making our shopping go further.

Waste could be reduced by simple steps such as storing fruit and vegetables in the fridge to make them last longer.

Tighten your belts: Gordon Brown with Japanese Prime Minister Yasuo Fukuda today at the start of the G8 Summit

While the Prime Minister was preoccupied with his household management tips, a joint report by the U.S. government and the Organisation for Economic Co-operation and Development was warning world food prices will rise by an average of 5 per cent this year  -  and keep climbing for another decade. 

Mr Brown, meanwhile, wants us to rediscover the thriftiness that was once a watchword for British housewives.

A report commissioned for the Prime Minister will today warn that an astonishing 4.1million tons of produce that could be eaten is being wasted every year.

Households could save £420 a year by throwing away less food, it concludes.

Mr Brown will use this week's G8 meeting of world leaders in Japan to push for international action to help halt increases in the cost of staple products, which have left many families struggling.

On his way to the G8 meeting, Mr Brown said: 'If we are to get food prices down we must also do more to deal with unnecessary demand such as all of us doing more to cut our food waste which is costing the average household in Britain about £8 per week.'

He hoped to agree a global plan to combat rising prices. 'That's why I am proposing we take action to both increase the global supply of food and reduce unnecessary demand.

'We will be discussing at the G8 how we can help Africa realise its great potential as a food producer and we would like to see production of key food stuffs in Africa double over the next five to ten years.'

In the last year, agricultural prices have increased by 40 per cent and oil prices doubled to $145 a barrel, with devastating effects for the economy.

Milk, eggs and bread have seen some of the biggest rises in recent months.

The U.S./OECD report says beef and pork will go up 20 per cent by 2018, sugar and rice 30 per cent, wheat and maize 40 to by throwing away less food, it concludes.

Mr Brown will use this week's G8 meeting of world leaders in Japan to push for international action to help halt increases in the cost of staple products, which have left many families struggling.

Make your shopping go further: Families urged to shop in a more thrifty manner for their food (posed by models)

He hoped to agree a 'global plan to combat rising prices. 'That's why I am proposing we take action to both increase the global supply of food and reduce unnecessary demand.

'We will be discussing at the G8 how we can help Africa realise its great potential as a food producer and we would like to see production of key food stuffs in Africa double over the next five to ten years.'

In the last year, agricultural prices have increased by 40 per cent and oil prices doubled to $145 a barrel, with devastating effects for the economy.

Milk, eggs and bread have seen some of the biggest rises in recent months.

The U.S./OECD report says beef and pork will go up 20 per cent by 2018, sugar and rice 30 per cent, wheat and maize 40 to

60 per cent, butter 60 per cent and vegetable oils 80 per cent. Today's Cabinet Office report will recommend action at home to help bring down demand for food.

Families are throwing away around one third of all the food they buy, experts say.

Forty per cent of the wasted produce is fruit and vegetables. More than half of consumers leave fresh produce out in a fruit bowl or larder.

Government experts are advising them to keep fruit and vegetables in a fridge, which research suggests can extend its life by up to a fortnight.

Excessive waste: 4.1million tons of produce is thrown away every year

Their report underlines the extent to which Britain has become dependent on cheap produce, making us more vulnerable than ever to global price rises. In 1984, the average UK household devoted 16 per cent of its expenditure to food, but that is now down to just 9 per cent.

The report warns that having been broadly stable for 20 years to 2005, global food prices have risen significantly.

It blames poor harvests in some exporting countries; higher costs for energy, fertiliser and transport; farmers shifting to grow green ' biofuels'; and a long-term rise in demand for grain to feed a growing global population.

The finding on biofuels is embarrassing because world governments have pushed farmers to produce crops used to make the environmentally friendly fuels. But biofuels are thought to have pushed food prices up by as much as 75 per cent because they have caused shortages of wheat and maize.

Today's report concludes that urgent action needs to be taken both to reduce demand for food and increase supply to avert a global crisis.

Experts say cereal production needs to increase by 50 per cent and meat production by 80 per cent by 2030 to meet demand.

Mr Brown is to call for investment to double production in Africa of key food staples  -  such as maize, sorghum and rice  -  in the next five to ten years.

The Government is also to court controversy by suggesting that genetically modified crops could play a significant part in increasing yields.

Mr Brown will also propose a new expert panel, similar to the International Panel on Climate Change, to examine longterm trends on food supply.

He will push other G8 leaders to move towards agreement on the 'Doha round' of world trade talks, which have been stalled for more than two years.

Mr Brown's message to Britons to do their bit by throwing less food away sits unhappily with the excesses world leaders will enjoy at the G8 summit, which is costing more than £280million.

Food is likely to be at the heart of the G8 summit when Mr Brown arrives with seven other world leaders.

Not least because they will have eight official dinners at the lakeside Windsor Hotel Toya in north Japan.

At the culinary helm is Katsuhiro Nakamura, a Michelinstarred chef, who has flown in a team of 50 helpers.

Many ingredients are expected to include the vegetables and seafood for which Hokkaido - the northernmost island of Japan - is renowned. Whether the leaders will be brave enough to try raw sea urchin - a famous Hokkaido dish --remains to be seen.

The chef has also created one international signature dish: the G8 pate. It contains a key ingredient from each of the eight nations - including black truffles from France, ham from Italy and mushrooms from Japan.