Scientists at one of the world's oldest plant research centers in Britain are conducting their most high-profile GM trial to date. It has rekindled debate and protest.
In its beautiful grounds in Harpenden near London, a team at Rothamsted Research has genetically engineered wheat to produce an odor that repels one of the crop's main pests - aphids.
To do this, they are using a pheromone called (E)-β-farnesene to trigger a "social response" in aphids.
Although GM trials are common in the laboratory, this wheat crop experiment is taking place in a field near the research centre. It will be studied for the next two years.
If the aphids are successfully repelled - as in the lab - it is hoped the development will save wheat crop from pest damage and reduce the need for pesticides.
But as the first open air trial of GM in a decade in Britain, the experiment has caught the attention of pro and anti-GM activists worldwide.
Food chain alert
Since the aphid-repelling wheat was planted earlier this year, Rothamsted has been the target of a sustained anti-GM media campaign, a protest, vandalism and even a cyber attack.
A group called Take the Flour Back threatened - but failed - to destroy the crop during a protest in May. It warned that if the trial was allowed to continue, the pollen from the GM wheat would fertilize conventional crops in the area.
If that happens, the group argues, it will be impossible to stop the GM wheat from entering the food chain.
Rothamsted's wheat crop is now surrounded by a high wire fence and is guarded around the clock by a private security firm. Even the researchers have to pass through several security checks before they can take samples.
"It's very sad," says Professor John Picket, who's in charge of the project.
"Sad because obviously we haven't explained things enough to alleviate their worries. And it's sad that they would try to destroy an experiment that was legally sanctioned," says Picket.
Media campaign counter-attack
In the lead up to one protest against the crop at the end of May, the researchers launched their own media campaign to counter what they saw as the myths perpetrated by anti-GM groups.
They called on the campaigners to refrain from destroying the GM crop, which they say represents a "paradigm shift" in GM technology.
"What we've been doing in the past is using genes to make proteins," explains Picket, "and what we're doing now is putting genes for enzymes into the plants and the enzymes produce the chemical that we're interested in."
The ability to produce the aphid alarm pheromone, (E)-β-farnesene, is naturally present in many plants, but not in wheat, where the scientists say it could be most useful.
Transforming normal spring wheat into GM wheat is the most delicate part of the experiment.
Huw Jones, another lead researcher, says this involves designing the two required genes in a lab. The genes are tweaked to appear more like a wheat gene and then "shot" into the wheat cells using a specialized gun.
But the talk of a new generation of GM crops doesn't convince anti-GM campaigners, who fear the spread of GM in the British countryside.
"The risk is small, but it's not zero," says Robert Kiley from campaign group GM Freeze.
Kiley argues that neither the general public nor farmers want this trial. He says it is driven by a desire to commercialize the technology as a product and make money.
The scientists at Rothamsted deny this. They say the GM wheat project is publically-funded and the results will be made freely available when the experiment is concluded in two years' time.
They are also keen to stress the measures that have been taken to minimize the risk of cross-pollination. These include buffer zones of barley and conventional wheat around the GM crop. They are also using a variety of spring wheat that pollinates later than most of the local varieties of winter wheat.
But for those who believe the public have a right to choose between GM and non-GM these measures fall short of their expectations. They cite cases in America and Spain, where organic farmers have found they can no longer sell their crop due to contamination from nearby GM crops - despite precautionary measures there.
They also say people in the UK and the rest of Europe - where only one type of GM maize is currently grown - are among the most skeptical about GM in the world.
Mark Lynas is a writer and environmentalist who used to advocate the destruction of GM crops but now supports their use. Lynas believes the Rothamsted trial could prove to be a turning point in attitudes towards GM in the UK.
Lynas says the scientists have managed to convince people that their experiment should at least be allowed to go ahead and the results yielded before any conclusions are drawn about the viability of the crop on a larger scale.
"Most of the opinions I saw expressed from the general public were in favor of the scientists," says Lynas. "The debate was framed not in the sense of are you pro or anti-GM, which might have had a different answer, but are you pro or anti destroying scientific research. And people are not in favor of destroying scientific experiments before the results can be yielded."
With their valuable crop under guard, the researchers at Rothamsted will be hoping that he is right.
Author: Robin Powell, Rothamsted, near London
Editor: Zulfikar Abbany