Millions of genetically modified insects designed to destroy food crop pests could be released into the countryside.
The Government is considering plans by a British company for the 'open release' of a GM strain of the diamondback moth, which it has developed.
Diamondback moths attack cabbages, broccoli, cauliflowers and similar crops.
With the GM strain a lethal gene is inserted into the male of the species so that when they mate with wild females, their offspring die almost immediately, causing the population to crash.
That could lead to increasing crop yields and profits for farmers.
The company involved, Oxitec, is keen to begin trials next year, but it faces opposition from groups who say the untested technology could threaten wildlife and human health.
The idea that man is 'playing God' in this way is also controversial.
Dr Helen Wallace, the director of GeneWatch UK, who has sat on government advisory bodies, said the release of GM 'Frankenmoths' is potentially disastrous.
'Mass releases of GM insects into the British countryside would be impossible to recall if anything went wrong,' she said.
'Changing one part of an ecosystem can have knock-on effects on others in ways that are poorly understood. This could include an increase in different types of pest. Wildlife that feeds on insects could be harmed if there are changes to their food supply.
Oxitec's chief executive said there was a demand from British farmers for genetically modified diamondback moths and that UK trials could start next year.Hadyn Parry said using GM insects to kill the pests that prey on food crops is better for the environment than harsh chemical sprays.
'Normally if I go over a crop with a pesticide, I kill all the insects that chemical touches, whether they are the ones I want to kill or whether they are beneficial,' he said.
Mr Parry added that it had been decided to genetically modify the diamondback moth because it develops resistance to chemical pesticides very quickly.
'In terms of the technology, it is ready now,' he said. 'We could do a trial in 2012, subject to what the regulatory authorities want us to do.'
He said he expects there will be opposition to the technology in the UK and Europe, but that 'regulators are really keen on making sure that there is no harm to the environment or unforeseen consequences.'
'GM insects that bite animals or humans could cause allergies or transmit diseases and new diseases might evolve.'
The Oxitec team of scientists, based in Oxford, insist these modified insects are better for the environment than the harsh chemical sprays currently used to kill pests.
The firm, which is supported by grants from the taxpayer, is developing a number of GM insects that would be used in Britain and around the world to protect crops and combat disease in humans.
Oxitec has contacted the Health and Safety Executive to ask what controls, if any, should be put in place around GM moth trials.
A scientific paper written for the HSE's Scientific Advisory Committee on Genetic Modification details how trials would work.
There are a number of scenarios, ranging from open release into fields to a more controlled experiment using polytunnels with insect proof screens at each end.
Dr Wallace has accused Oxitec of trying to sidestep regulations designed to police GM technology.
But the company appears to have the support of the Department for Environment, Food and Rural Affairs, which has raised no objections to open field trials.
This raises questions about the role of Environment Secretary Caroline Spelman, who is a long-term supporter of GM technology.
The scientific paper points out that the proposals would effectively circumvent the policing regime – the Deliberate Release Regulations – set up to scrutinise the release of GM organisms.
It then admits that approving trials through the HSE 'raises difficult legal and policy issues'. Usually, GM trials have to be approved by Defra.
Significantly, the paper makes clear that Defra has not objected to open field trials, providing there are guarantees for the safety of humans and the environment.
Oxitec says all the GM moths carry a lethal gene and would die within a few days of release. This is known as 'biological containment' and Oxitec argues that it is so successful there is no need for any physical barriers to stop the insects flying away.
The paper states: 'For an "open" release to go ahead the extent of the biological containment would have to meet two legal tests.
'First, it should be sufficient to limit contact with humans and the environment. Second it should provide a high level of protection to humans and minimise the risk of harm to the environment.'
A Defra spokesman said that while its officials and advisers have discussed Oxitec's plans, there has not yet been a formal application for a trial. Consequently, the department has not reached a view on whether it should go ahead.