Sir: In the light of the recent arrest of Greenpeace activists for destroying GM crops in Norfolk, it seems to me that much of the debate about these crops is missing the point. Not surprisingly, potential damage to human health has grabbed the headlines, but this seems the least of the possible problems.
Genetic pollution of other crops and native plants is also probably not as apocalyptic as is sometimes suggested. For example, many weeds have already evolved resistance to some herbicides, without human assistance, but they have not gone on to take over the world.
The real problem, frequently overlooked, is the potentially huge changes to farming practices - changes that may be as great as those that followed the introduction of tractors, pesticides and chemical fertilisers.
Over the last 50 years, these changes have devastated wildlife in the British countryside. Even today we do not know the final effect of these changes, and huge sums of government money are spent every year in attempting (mostly unsuccessfully) to slow or reverse the most damaging effects.
So-called farm-scale trials of the sort destroyed by Greenpeace will provide only the smallest taste of the revolution that widespread cultivation of GM crops would eventually bring. The only certain thing about a GM future is its unpredictability.
Unlike the post-war agricultural revolution, this is one we don't have to have, and one the public do not want. Whether we want commercial cultivation of GM crops is not, in the final analysis, a scientific decision, but a political one. We already know enough to say "no" if we want to.
Dr KEN THOMPSON