Until very recently the word "organic" conjured up the image of a back- to-basics cult, the membership of which was overly excited by the prospect of Doomsday and liable, in the meantime, to grow dog-eared vegetables for like-minded obsessives. Prince Charles was himself mocked and vilified for his environmental preoccupations. Undeterred, he had the vision, obstinacy and courage to defy conventional opinion and to convert his estate at Highgrove into an organic farm. Today it is an ecological - and commercial - showpiece.
Eighteen months ago, on the 50th anniversary of the Soil Association, the Prince made the keynote speech in which he honoured an "immortal line" of its founder, Lady Eve Balfour, that "the health of soil, plant, animal and man is one and indivisible". That sensibility has always been his - and the organic movement's - lodestar; today it is one of ecology's truisms.
The side effects of treating agriculture as an industrial process - the BSE nightmare, the nitrates that pollute soil and water, the pesticides that infest produce, the antibiotics that accelerate livestock growth, the genetic tampering with crops to increase yields - are no longer accepted unquestioningly as a price worth paying for cheap food. The multinational conglomerates may still hold the international food chain in an armlock but they are now on the defensive. Their implicit assumption that food production entails a chemical war of attrition against nature itself is under ever sharper scrutiny. Although the consumer is not yet in revolt, the evidence of revulsion is evident.
The organic movement believes that our species is not only dependent on the natural world but is also part of it. Accordingly, we are committed to producing food in ways that avoid treating any other organic matter - from fungi and bacteria to insects and mammals - as an "enemy" to be destroyed. We therefore forbid the use of chemical fertilisers and we regard antibiotics as a treatment of last, not first, resort and we set standards for animal welfare that are even higher than those recommended by the RSPCA. For all these reasons the arable deserts and the factory farms which now disfigure so much of rural England are incompatible with our farming methods.
For those, like the Prince, who champion the cause of rural communities, organic production - which is labour intensive and committed to local markets - also offers a real prospect of economic regeneration and social renewal. But, for most consumers, the main attraction is clearly the character and quality of the food we produce.
This weekend, the Soil Association has had to disappoint hundreds of applicants eager to attend its annual conference at Cirencester because there was space for only 500 participants. As if to confirm that the organic movement is no longer on the fringes, the keynote speech yesterday was delivered by Dino Adriano, the new chief executive of Sainsbury's, one of the co-sponsors of the event.
The supermarkets are not in this just for the fun of it but because their customers are in earnest. The polls tell us that the majority of the British public would "go organic" if they could afford it and if they could find the produce. At the moment, though, demand for organic food in the UK so far exceeds supply that more than 70 per cent of the organic produce sold in supermarkets has to be imported from the continent. Although the proportion of Britain's farmland that is now either fully organic or "in conversion" has doubled over the past year, this still represents a mere one per cent of the potential acreage - and lags behind the rest of Europe, which is projecting 10 per cent organic by 2007.
This predicament owes much to the attitudes of a clique of senior civil servants at MAFF who, until recently, chose to treat the organic movement as an irrelevant cohort of idealistic muddletops with no understanding of the "real world". In this "Yes, Minister" habitat even politicians who were sensitive to the organic voice (like William Waldegrave and John Gummer) were never in the department for long enough to override the narrow but implacable certainties of these officials. In thrall to the voice of the big battalions in the farming industry and deaf to the environmental entreaties of competing lobbies, the narrow vision of these officials held sway for a generation.
But in the past 18 months there has been a distinct shift. Battered by their part in the BSE debacle, these obdurate bureaucrats found themselves answering to Jack Cunningham, whose smooth demeanour barely concealed the instincts of a political bovver boy with nothing to lose. Although his reaction to the collapse in agricultural prices veered towards the brutal, he was canny enough to detect the political attractions of our totems and sharp enough not to sneer at them.
Instructing his officials to take the organic case seriously, he required them to divert existing funds into organic research; he established a free "organic" advice service (administered by the Soil Association) and, after tortuous negotiations, he doubled the "conversion" payments for "conventional" farmers who chose to take the organic plunge. Not enough, but not bad. Last autumn, soon after he moved on to become the cabinet "enforcer", Cunningham followed in Prince Charles's footsteps to deliver the Soil Association's annual lecture.
Declaring that the principles of the organic movement coincided precisely with the agricultural, environmental and social priorities of New Labour, he became the first cabinet minister of any government to pay his pounds 20 and sign on as a member himself. His successor, Nick Brown has - so far - followed in his footsteps.
Albert Schweitzer wrote "man has lost the capacity to foresee and forestall. He will end by destroying the earth". The Soil Association believes otherwise: that we can foresee, we can forestall, and therefore that the earth can be saved.
Jonathan Dimbleby is president of the Soil Association.