At the heart of the debate is a struggle for the soul of British consumers, between agrochemical interests and new technology on one side and organic farmers on the other. Consumer groups yesterday sided with the Prince, calling for fuller labelling of genetically modified (GM) foods.
Biotechnology companies defended their work after the Prince aired in a newspaper article his worries about inserting genes into crops .
Dr Colin Merritt, technical manager of Monsanto, said that genetic modification was an extension of practices that had existed for thousands of years: "All that's different is that we now understand the chemistry and the genetics far more than we did and we can use a slightly wider range of choice of material."
A spokesman for Zeneca, the British biotechnology company, added: "Prince Charles is entitled to his views, but we believe that on a scientific basis the biotechnology is regulated correctly, and there are correct regulatory measures in place before a product goes to market."
Europe insists on far more stringent testing procedures than the US for new GM foods. Proponents insist that biotechnology which can introduce new genes into crops from entirely different species - or even from animals into plants - is necessary both to meet the world's increasing demand for food, and to reduce the need for artificial chemicals that could affect the environment.
Patrick Holden, director of the organic movement's Soil Association, warned that most of the new crops would be herbicide-resistant, and that there were also unforeseen health risks "which if they came to pass could be irreversible and difficult to counter".
He suggested that in 10 years all the main staple food crops might be modified: "This is a technology which is going to be imposed on all of us whether we like it or not, and it will deny consumers choice."
Prince Charles compared the possible effects to those of BSE - mad cow disease - in an article in a daily newspaper. He wrote: "The lesson of BSE and other entirely man-made disasters in the cause of 'cheap food' is surely that it is the unforeseen consequences which present the greatest cause for concern.
"Once genetic material has been released into the environment it cannot be recalled. The likelihood of a major problem may be slight, but if something does go badly wrong we will be faced with the problem of clearing up a kind of pollution which is self-perpetuating."
The National Consumer Council (NCC) said the Prince was more in tune with consumers than EU policy makers who had failed to insist there should be clear labelling.
NCC director Ruth Evans said: "Consumers want to know how their food has been produced because, for a variety of reasons, many do not wish to eat foods from GM sources."
Prince Charles suggested that farming GM soybeans lead to use of pesticides where "when the crop is sprayed, every other plant in the field is killed. The result is an essentially sterile field, providing neither food nor habitat for wildlife."
For Monsanto, Dr Merritt responded: "In the United States the amount of insecticide used on one crop alone had been reduced by two million litres."
He rejected as "irresponsible nonsense" claims that his firm was seeking corporate power by selling farmers both seed and its own patented pesticide. Farmers did not have to buy his products, he said.Reuse content