The anti-GM activists who are threatening to destroy experiment on genetically modified crops said they feel they have "no choice" and allowing the crop to continue would be an "act of terrorism."

The anti-GM activists who are threatening to destroy experiment on genetically modified crops have said they feel they have "no choice" and allowing the crop to continue would be "completely irresponsible."

In response to a plea from John Pickett, a chemical ecologist leading pioneering research at Rothamsted in Hertfordshire, Matt Thomson, a spokesperson for the group Take the Flour back said the scientists were being "rather melodramatic."

Pickett, in an open letter published on Wednesday, said the activists risked destroying their lives' work and ruining a project that could protect the environment.

But the protesters argue that similar experiments in Canada have leaked into the food-chain, costing farmers millions in lost exports.

"I am completely opposed to the crops being given open-air release. We've asked Rothamsted to remove it, we took a challenge to Defra last month, if you don't then we will. We don't want to be criminalised, but we don't feel we've got any choice," he told The Huffington Post UK.

"If we were to allow it [the crop] to flower we would be risking much more than any of the work that's been done on GM we would be risking generations of research.

"I think it's a case of there needs to be a full and frank debate on the science. GM is something which has been rejected time and time again by consumers. time and time again by farmers. There's no market for this stuff. Why is it being pushed on us again?

"Why is it risking the most important crop we have in the UK. That to me is an act of terrorism. It's completely irresponsible. I would hesitate to use the word terrorist because I think it's overused but I think they are acting irresponsibility."

The scientists at Rothamsted Research are conducting an experiment to create wheat that can more easily repel aphid attacks. But protesters, who are worried GM crops could carry viruses and be antibiotic resistant, say they are risking contaminating wheat and "robbing UK farmers of their livelihoods."

But Pickett, in an open letter to the group, claimed: “We can only appeal to your consciences, and ask you to reconsider before it is too late, and before years of work to which we have devoted our lives are destroyed forever,” he said.

On Wednesday morning organic farmer Gerald Miles, who plans to join the protests, said the experiment would "ruin the market for wheat exports in the UK."

He denied it was an exaggerated claim, telling BBC Radio 4's Today programme: "They can't give us a written guarantee that this won't happen because there's proof of it happening all over the world."

Thomson said the group were not seeking to "cause terror."

"We are being very public and accountable in everything that we do," he said. "This is a publicly funded experiment and the scientists will still be paid at the end of this, you can't say the same with UK farmers. People have lost thousands of pounds, what you are talking about is potentially robbing UK farmers of their livelihoods which I think is absolutely deplorable."