Sorry,Your Highness, but science just isn't your field

He shows a common misunderstanding of how agricultural science works. What's worse, though, is that his comments risk reinforcing the mistrust felt by much of the public about how their food is produced.

It might not fit the prince's image of honest toil in the fields but agriculture has always evolved technologically. The agricultural revolution of the past 1,000 years or so has fallen into three overlapping stages - mechanical, chemical and genetic.

The first involved the use of animals and then powered machinery to drive cultivation equipment and tools. The second developed fertilisers such as phosphate to enhance the fertility of soils. The third was about the development of improved varieties of many crops.

The last is the key one here - not least because, from his comments, Prince Charles appears to be against hybrid seeds as well as GM ones. One hundred years ago a scientist named George Shull found that by crossing two different varieties of maize, the new strain produced considerably higher yields and grains of better and more consistent quality.

Many people found this characteristic both amazing and somewhat difficult to believe - particularly as subsequent generations failed to exhibit these characteristics to the same extent, which meant farmers were obliged to purchase new seed each year. Some people accused Shull of practising "witchcraft" and of producing a technology for his own ends. The similarity between these facts and Prince Charles's position is remarkably similar.

This technique is known as hybridisation and almost all maize now grown is from this "F1" seed - even though this costs farmers more than if they saved their own. Patrick Holden, who is both director of the Soil Association and a close friend of the prince, openly admits that he grows F1 carrots, which are sold as organic. Presumably Prince Charles approves of this practice.

I am reminded of the suggestion made some time ago by Professor Steve Jones of University College London that the best thing the prince could do would be to take an A-level in biology: it would help him to understand the irrationality of his position.

Modern seed varieties, whether bred by hybridisation, random genetic mutation or by the more precise methods used by the "clever" genetic engineers (as the prince describes them), continue to make a significant contribution to agricultural productivity throughout the world. GM technology is merely another stage in the process of producing better varieties of crops.

Like the other stages of the agricultural revolution, it comes with potential downsides. But these are far outweighed by the enormous advantages it offers: the potential to increase dramatically both yields and the quality of crops harvested.

Moreover, GM crops are still in their infancy: the future gains are extremely exciting. Think of the many thousands of people in Asia who suffer blindness from a lack of vitamin A in their diet: rice, their primary source of carbohydrate, contains no vitamin A. Yet the insertion of a single gene into rice plants could help reduce this appalling condition dramatically - and this has been made available free of charge by its developers.

Then there are the many farmers who would prefer not to spray their crops with an insecticide when they could grow a variety - say of cotton - resistant to certain pests.

Or ask the thousands of Spanish, German and French farmers already growing GM varieties of maize whether they should be banned from doing so and you will receive a very clear answer. And they are, relatively speaking, the rich ones. Of the world's 12 million farmers, more than 90 per cent are regarded as "resource poor" and derive more than 80 per cent of their income from farming. For them, GM crops have the potential to transform their lives for the better. We cannot deny the millions of people who might benefit from this science by demanding that it be stopped, as Prince Charles is doing.

He also blames various ills on modern agriculture more generally - yet fails to see that GM technology could be the solution. He is worried, for instance, about the huge salination problems faced by farmers in many parts of the world. Soil becoming too salty is indeed a problem in places - but GM technology offers us the chance to develop crop varieties that will not just survive but thrive in such conditions. Are we to understand that the prince would like us to abandon the best chance we have of producing crops from areas of land, which, for a variety of reasons, have become unusable? Surely not. He frets that the world's food production is in the hands of a few massive companies at the expense of many small farmers. Yet it is only through those companies' substantial investment in science that we consumers will ever have the opportunity to benefit from this technology.

It's not easy for the scientific community to address the concerns of the small but highly influential organic farming lobby: the public don't speak our language but they buy their organic beans. However, scientists have to try. We need to use data properly assessed by independent experts such as the Food Standards Agency.

The FSA finds no reason to believe that GM foods pose any higher risk than foods made from conventionally farmed ingredients. Indeed, I would argue that because they are far more rigorously tested than other foods, GM products are almost certainly safer.

By the same token, organic farmers use pesticides, and some very dangerous ones at that, including copper sulphate, a soil sterilant.

As Prince Charles sips his favourite whisky, he might like to consider that it is almost certainly made using grain from plants bred thanks to advances in plant biotechnology. Yes, your Highness - GM really does benefit us all.

Jonathan Harrington is a chartered biologist specialising in agricultural crop technologies.