The Prince of Wales has warned the development of genetically modified crops risked creating "the biggest disaster environmentally of all time".
In a passionate intervention on the issue of GM food, Charles accused multi-national corporations of conducting an experiment with nature which had gone "seriously wrong".
He told the Daily Telegraph: "What we should be talking about is food security not food production - that is what matters and that is what people will not understand.
"And if they think also that somehow it's all 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."
Charles said relying on gigantic corporations for the mass production of food would threaten future food supplies. And he said small farmers would be the victims.
"If they think this is the way to go we will end up with millions of small farmers all over the world being driven off their land into unsustainable, unmanageable, degraded and dysfunctional conurbations of unmentionable awfulness then you count me out. I think it will be an absolute disaster."
Charles' intervention comes at a time when soaring food costs and shortages are putting more pressure on the GM debate.
The price of food has been pushed up worldwide by poor harvests, some of which may be due to climate change, rising fuel prices, market speculation and the diversion of land into biofuel production.
The biotech industry says GM technology can be used to tackle hunger and poverty by delivering higher yields and reducing the use and therefore cost of pesticides.
And earlier in the year Environment Minister Phil Woolas suggested opposition to genetically modified crops may have to be rethought in the light of the global food crisis.
But green groups and aid agencies fear claims about the potential benefits are not being borne out in practice.
Critics say there is no evidence to show GM crops boost yields.
And they warn that rather than tackling poverty in developing countries, much of the GM crops grown - the vast majority of which are in North and South America - are used for animal feed or biofuels.
Charles, who has an organic farm on his Highgrove estate, told the newspaper he wanted to see more family run co-operative farms.
He denied this was trying to turn back the clock and said farmers must work with nature and not against it.
At the end of last month, scientists told the Government field trials of GM crops in the UK need better protection to allow researchers to assess their benefits.
They said the location and details of small-scale trials could be kept from the public to prevent them being vandalised by anti-GM protesters.
And they said the number of field trials had declined in recent years because of sabotage, damaging the UK's ability to inspire innovation and commercial investment.
A Defra spokeswoman said: "As we have said many times, there is an important debate to be had on the potential role of GM crops in the future, and we welcome all voices in that debate.
"Safety will always be our top priority on this issue."Reuse content