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Experiments by British academics have found that GM insects could be used to wipe out fruit fly pests that damage crops such as oranges, peaches, apples and pears.

Genetically modified versions of the Mediterranean fruit fly have been created using controversial technology developed by the UK bioscience company Oxitec.

Millions of male GM flies have been created in the laboratory to include a gene which means that when they mate with wild females, any resulting female larvae die before reaching maturity.

Genetically modified versions of the Mediterranean fruit fly have been created using controversial technology developed by the UK bioscience company Oxitec

The resulting fall in the number of female fruit flies should, in theory, lead to a collapse in the total population which will mean less damage is caused to food crops.

Oxitec has promoted the technology as an alternative to the use of harsh chemical pesticides to protect food crops and so boost yields and has held talks with UK government agencies to run trials in this country.

However, critics predict a consumer backlash over concerns that the dead GM larvae or maggots from the 'Frankenflies' will remain inside or on the harvested fruit which reaches the high street and kitchens.

A team of researchers from the University of East Anglia has carried out trials using the Oxitec GM fruit flies in closed greenhouse trials involving lemon trees on the Greek island of Crete.

The work was part-funded by the UK taxpayer through the Natural Environment Research Council and Oxitec itself, which is based in Oxford.

The Oxitec approach represents a variation on a current technique to control pest numbers, which involves exposing male fruit flies to radiation to sterilise them.

These are then released to mate with wild females under a regime known as the Sterile Insect Technique (SIT), with the aim of reducing the total population.

Lead researcher Dr Philip Leftwich, from UEA's school of Biological Sciences, suggested creating GM fruit flies is likely to be more effective in reducing pest numbers than SIT.

He said: 'The Mediterranean Fruit Fly infests more than 300 types of cultivated and wild fruits, vegetables and nuts. It is a real pest to agriculture and causes extreme damage to crops all around the world.

'Of all of the current techniques used to control these flies, SIT is considered the most environmentally friendly as it uses sterile males to interrupt matings between wild males and females. The down side is that these males don't tend to mate as well in the wild because the irradiation method used for sterilisation weakens them.

'Our research looked at whether releasing Oxitec flies, which are genetically engineered so that only male fly offspring survive, could provide a better alternative.

'The genetically engineered flies are not sterile, but they are only capable of producing male offspring after mating with local pest females - which rapidly reduces the number of crop-damaging females in the population.

'Using this method means that the males do not have to be sterilised by radiation before release, and we have shown they are healthier than the flies traditionally used for SIT.

'We simulated a wild environment within secure eight-metre greenhouses containing lemon trees at the University of Crete. When we tested the release of the genetically modified male flies, we found that they were capable of producing rapid population collapse in our closed system.

'We believe this is a promising new tool to deal with insects which is both environmentally friendly and effective.'

The next stage of the research will be to gain approval for open-field studies, effectively release the GM 'Frankenflies' into the wild to assess the impact on the wild pest population.

Oxitec has developed a number of GM insects, which it believes could deliver real benefits in terms of farming and human health.

Oxitec has also created GM versions of the caterpillar of the Diamond back moth, which is a world-wide pest that can cause severe damage to vegetable crops particularly cabbage, broccoli, cauliflower, sprouts, swede and turnips

It has used the same technology to create GM mosquitos in a bid to reduce wild populations which spread dengue fever to humans. Trials have been carried out in the Cayman Islands and Panama.

It has also created GM versions of the caterpillar of the Diamond back moth, which is a world-wide pest that can cause severe damage to vegetable crops, particularly cabbage, broccoli, cauliflower, sprouts, swede and turnips, the Tuta absoluta caterpillar, which is a particular threat to tomatoes.

Dr Helen Wallace, the director of GeneWatch UK, said there is likely to be consumer opposition to the technology.

'Releasing millions of Oxitec's GM flies would contaminate fruit with GM maggots, which are genetically programmed to die inside the fruit. This will damage the market for the fruit and could harm human health,' she said.

'Living GM flies could also be transported in the fruit, as only the females are programmed to die. These could spread worldwide with unknown environmental consequences.'

She said Brazil's GM regulator has already given approval for Oxitec to release GM fruit flies into fruit orchards as part of an experiment, but the Brazilian Government and growers are hesitating because concerns consumers will reject the fruit. Britain is a major importer of melons, mangoes, grapes, apples, papayas and plums from Brazil.