It might be a while before they appear on the shelf at Tesco.

But scientists claim adding insects to our diet would be good for us and the environment.

Crunching into crickets or snacking on grilled caterpillar is apparently a means to a nutrient-rich diet that also helps reduce pests and puts less strain on the planet than eating conventional meat.

Some insects in their dried form are said to have twice the protein of raw meat and fish, while others are rich in unsaturated fat and contain important vitamins and minerals.

Experts believe they could one day be marketed as a healthy alternative to fatty snacks.

In most of Europe, bug-eating is largely restricted to the belated realisation that there has been an unwelcome addition to the salad.

It is common elsewhere, however, with some 1,700 species of bug eaten in 113 countries.

In Taiwan, stir-fried crickets or sauteed caterpillars are delicacies. A plate of maguey worms - larvae of a giant butterfly - sells for £12.50 in smart Mexican restaurants.

Sago grubs wrapped in banana leaves go down well in Papua New Guinea, as does dragonfly in Bali.

In many parts of south-east Asia market stalls sell insects by the pound and deep-fried snacks are served up as street food.

Insects are arthropods, much like crab, shrimps and lobster which are all accepted by the European palate. In North Africa locusts are sometimes called sky prawns.

But Patrick Durst, of the United Nations Food and Agriculture Organisation, said that if consumers were to be tempted to broaden their culinary horizons the trick might be to make the bugs look more palatable.

'You need to get the food into a form where someone doesn't have to look the bug in the eye when they eat it,' he said.

Earlier this year the Food and Agriculture Organisation held a conference to discuss how entomophagy - eating insects as food - could contribute to sustainable development.

Bug-farming preserves forests - which are needed to attract insects - and is encouraged in some countries.

As for pesticides, some experts have pointed out the irony of using chemicals to get rid of bugs that are more nutritious than the crops they prey on.

In Thailand when pesticides failed to control locusts, the government urged locals to eat them and distributed recipes.

Chef Paul Cook, who supplies exotic and unusual food through his Bristol-based business Osgrow, has sold a range of insects including locusts.

He said: 'You have to get past your feeling when you look at a whole locust or cricket. They are very clean and nutritious.

'But I don't think we are going to see Jamie Oliver encouraging us to have sky prawns on the school menu.'