Britain's Prince Charles said on Wednesday the widespread use of genetically modified crops would be the biggest environmental disaster of all time.
The 59-year-old heir to the British throne is well known for supporting organic farming, but his comments published in an interview with the Daily Telegraph were his most outspoken yet on GMO foods.
His views will strike a chord in Britain where biotech crops -- widely grown in North and South America -- have faced significant opposition with concerns centred on food safety and possible environmental impacts.
Charles said multinational food companies were conducting a "gigantic experiment with nature and the whole of humanity which has gone seriously wrong".
If large companies took over the mass production of food, it would hurt small farmers and the environment, while "excessive approaches to modern forms of agriculture" had damaged water supplies in India's Punjab and in Western Australia, he said.
"What we should be talking about is food security, not food production -- that is what matters and that is what people will not understand," he said.
"And if they think it's somehow going to work because they are going to have one form of clever genetic engineering after another, then again count me out, because that will be guaranteed to cause the biggest disaster environmentally of all time."
His comments come as a wave of food inflation has reopened the debate on how science can boost agricultural production.
Critics of GMO crops say they are environmentally unfriendly and could potentially harm those who eat them. But supporters say they can raise yields, cut costs, and provide other benefits to improve food and feed the world's hungry.
Earlier this year Britain's chief scientist John Beddington said GMO crops should not be shunned as agriculture seeks to respond to rising food demand, particularly from China and India, at a time when climate change is expected to hit yields.