Of the four secondary schools which Quentin Gargan attended, two had profound effects on him for entirely different reasons. When he was 14, he went to a small provincial boarding school which he describes as an "outward bound type of school". Classes were in the morning, and in the afternoons, there were "horses, boats on the river, a lot of sailing. We used to build each other adventure courses".

This idyllic sounding Boy's Own type-school came with its own built in liability, and Gargan did not stay there long. "To be honest, I left because I was being abused," he explains frankly. "So it doesn't just happen in Christian Brothers - this was a Protestant school." He laughs with uneasy self deprecation into his peppermint tea. He says he tried to pursue the matter in later years, but got nowhere.

This sort of story is becoming horribly familiar, but what is remarkable is Gargan's philosophical - almost uncomfortably well adjusted - take on it all. "If I was to be honest and look back on the whole experience of that school," he says, "it was actually a very good school, and what happened happened, and became part of the rich tapestry of life."

He doesn't sound remotely cynical or ironic when he talks about this particular addition to the rich tapestry of life. "I don't feel now it has any debilitating effect on my life." If this is true, Quentin Gargan is a man of exceptional inner resources. He uses the expression "to be honest" like a mantra throughout his conversation, and he certainly sounds as honest as he says he is.

The other school which made an impact on him was St Columba's College in Rathfarnham, Co Dublin. "We had a vegetarian society there and there was a vegan who introduced a lot of us to alternative diets, and the concept of alternative diets," he explains with animation. The concept of healthy and alternative eating is usually lost on teenagers, but for Gargan it was the beginning of a life long dedication to the whole-food industry and the way food is manufactured.

Born in Dundrum, Dublin, in 1956, Quentin Gargan is the youngest of four siblings. "When I was growing up, Sunday lunch in our house was like a board meeting. I was brought up to be comfortable with business. We had a sweet factory, and a sweet shop and a wholesale business, J.M. Gargan and Company. It was started by my grandfather." He describes the sweets they sold as "pure trash, nothing to do with healthy eating. I'm definitely the white sheep of the family!"

At 16, he went to the RTC in Athlone and studied plastics engineering, more or less because it was there, rather than from any real interest. "Fortunately for me, the oil crisis happened the year I came out of college, so there were no jobs," Gargan says. He went on to work for Ericsson, programming telephone exchanges. At the same time, he went back to college at night and did a course in telecommunications. In a sudden burst of pride, he says: "I'm one of these people who could breeze through an exam. I didn't have to apply myself."

At 20, he changed direction again and went back to his roots, running a branch of the family sweet business in Tullow, Co Carlow. He was responsible for a workforce of 40 people, many of them his senior in years. Already, his personal code of ethics and his method of earning a living were beginning to collide. "I was never very happy that my working day consisted of shovelling another ton of sugar into the food chain."

Gargan had other responsibilities to consider by then too. He married Emer O'Neill at 20, and there were three children in quick succession. He also has a fourth child from a later relationship. "During that time, I used to suffer from desperate headaches, really debilitating." A homeopath helped him towards recovery. "It actually revolutionised my life again," he says, describing the sensation of felling well again. The return of his energy and the new interest in alternative medicine led him to open a small health food shop in Clonmel while also running the sweet business, a combination of jobs he calls "incongruous".

The health food shop provided him with a focus for his growing concerns about the food industry. "It's all old hat now, but the health food industry was very ahead of its times in criticising the food refining process. I mean, we're still there with a mission, but the mission has moved on now. In those days it was very basic - promoting muesli and yoghurt and wholemeal bread."

At 25, he set up his own business, Wholefoods Wholesale. He is still managing director of this company, which supplies many of the health food shops around the country with "the whole gamut of what you might find in such shops". At 28, he separated from his wife but is still in regular contact with all his children. Today, Wholefoods Wholesale employs 35 people. It has an annual turnover of £6 million, and operates on a profit sharing principle, which he says is "central to how the company works. I get the credit, but other people are actually the real backbone of the company."

The general public is probably most familiar with the name of Quentin Gargan as the spokesman for Genetic Concern, which was set up in March 1997. He is anxious to stress that, while he gets the publicity for the organisation as its spokesman, he feels "very unworthy, as if I'm riding on the back of other people all the time".

In November 1996, the first genetically engineered soya beans appeared on the scene. They were grown in the US, and then imported to Ireland. "Soya beans are almost an icon in the health food industry; they're in about 60 per cent of grocery products," Gargan explains. "The health food industry decided that genetically engineered soya was just not on. It was only one per cent of the crop at the time, but it wasn't being segregated. So we had no way of knowing which bean was which."

Long connected with the Irish Association of Health Food Stores, Gargan felt that he - along with several others - had to try to draw public attention to the issue of genetically modified food. Why? His answer is the textbook antithesis to the world of facts and science. "Sometimes you come to something from a gut reaction. I would rely on instinct quite a lot and look for something to follow it up. Instinctively, I just didn't like the idea of genetically engineered soya. It just wasn't what we wanted in the health food industry at all."

In January 1997, UK based company Monsanto applied to plant genetically engineered sugar beet in Carlow. One of the people alarmed by this application was Clare Watson, an environmental campaigner. In March of that year, she called a meeting of concerned individuals, one of whom was Gargan. Genetic Concern had its origins in that meeting, as did romance: Watson and Gargan are now partners.

Gargan defines Genetic Concern as "a voluntary organisation whose mission or purpose is to raise awareness of the potential risks of genetic engineering in food and in agriculture. We believe the further we deviate from nature in the way we produce our foods, the more likely it is to have an adverse effect on our health."

Genetic Concern, in a case taken by Clare Watson, went on to take Monsanto and the Environmental Protection Agency to the High Court. Watson challenged the permission given to Monsanto to conduct field trials on genetically engineered sugar beet on lands owned by Teagasc at Oak Park, Carlow. She lost the case, and in October of last year, was ordered to pay £400,000 in costs.

Gargan hadn't thought they would lose. He shakes his head emphatically. "We thought we had a good chance of winning," he says, "but what we didn't realise was that the case wouldn't look at the issues at all. It left us running a case based on procedures. Even on those issues we were surprised that the judge found against us on all those issues, and for that reason we have decided - Clare has decided - to take the case to the Supreme Court." An appeal has been lodged.

He doesn't think that losing the case did Genetic Concern damage, but admits that his partner was "devastated" by the outcome. Losing such a case, and then facing the subsequent financial strain would certainly test any relationship, but Watson and Gargan are most definitely still together. His face lights up every time he says her name.

The other positive aspect of the case is that it "honed our own arguments. We learned a lot about genetic engineering by taking the case, even though the evidence we prepared for court was never used. It highlighted the issue; put it in the public domain."

Genetic Concern hit the headlines again last week, when it was one of the 19 non governmental organisations (NGOs) out of a total of 21 which chose to pull out of the government's consultation process on genetically modified foods. These NGOs attended only the first of two day long sessions during which the arguments for and against genetically modified food and crops were to be discussed. Speaking for Genetic Concern, on the eve of the second debate, Gargan explained that they were distancing themselves because "environmental issues had been restricted unduly, while concerns about the health impact of GM foods were not given a full airing". The withdrawal of so many of the NGOs is undoubtedly an embarrassment for the Department of the Environment.

Perhaps surprisingly, Gargan is not vegetarian, although (unsurprisingly) he prefers to eat only meat which has been organically produced. Other aspects of his life reflect his concern for the environment. Last year, he bought Ireland's first electric car, which goes for about 30 miles before needing the batteries recharged. And he has just purchased 60 acres near Skibbereen, where he and Clare Watson intend to build an ecological guest house, which will have wind generated energy and an organic garden.

Genetic Concern is often aligned with the Green Party, but Gargan says "to be honest, I'm completely apolitical and would vote for the person every time, instead of the party". He has no political ambitions. However, while he may consider himself apolitical, his commitment to Genetic Concern and its associated issues is not dissimilar to that demanded of independent party politics. He reckons in an average week, he voluntarily works at least 40 hours on behalf of Genetic Concern. "Sometimes 50 or 60." This is on top of his own business. "You've almost no choice," he says. "We're all working out of a passionate belief of what we're doing."

When asked what he does in his free time, he gives a big, astonished, and rather nervous laugh. He's anxious to answer the question, but he's genuinely flummoxed by it. After a long silence, he says he likes to ramble and hill-walk, but it's an answer which sounds more like saying something for the sake of saying something.

Again he says of his work for Genetic Concern, that there's "almost no choice" in the matter. Except of course, he does have a choice. Nobody is forcing him to take on these issues. Privilege certainly comes into it: few people could afford to give an average of 40 hours a week to a job which pays them nothing except personal satisfaction.

Predictably, Gargan has taken flak from those who accuse him of jumping on the Genetic Concern bandwagon in the interests of promoting his own Wholefoods Wholesale business. "If I'd put half of the time and energy into my business that I put into Genetic Concern, I'd be a millionaire by now," he says dryly. He points out that the health food industry has always been a campaigning one, and reckons the next major issue is that of attempts to restrict the sale of herbal medicines.

In 1990, Gargan and his then partner, Lorna Burrow, set off in his yacht, New Leaf, with the intention of sailing around the world. Once under way, they abandoned the idea, settling instead for meandering down the African coastline, going ashore for longish periods of time. In all, Gargan was away three years, returning to Ireland at nine month intervals to see his children.

"I always wanted to travel and it was something I should have done when I left college. I really wanted to visit places and see how people lived and work on banana plantation, and to live in the mountains with the local people and so forth." He says the trip changed his priorities, and gave him a bigger world picture: but it really seems to have compounded the beliefs he already held.

"The trip taught me a much deeper sense of living in harmony with nature. We spent time visiting islands where people really lived an incredibly simple lifestyle: grew their own food, cooked it in their own earthenware pots, ate it out of dishes they'd made themselves and kalabashes with coconut spoons. They were really self sufficient, and they were the healthiest and happiest people I've ever seen.

"I don't think the lifestyle we live is sustainable in the long run, and everyone knows that. Humanity is going to have to make major changes if we're still going to have a planet to live on. I've never seen anyone as happy as these people who had a very simple lifestyle; I've never seen anyone from our civilisation who was anything like as happy," he insists. This is a statement which he clearly believes, yet which is also so simplistic and sweeping that it makes him sound a tad naive.

So what about his own definition of happiness? Where or when was Quentin Gargan happiest? This question proves even more difficult to answer than the one about what he does for leisure. First he doesn't answer it, just offers: "I actually think life gets better and better as you get older." Then he considers for some time. "I'm much happier when I hear good news. What I would regard as good news is . . . How can I describe it? We get a real buzz out of what we're doing - not just in Genetic Concern but in other issues we've worked with in the past - when you see a message getting across, and you see people changing." It's not unlike having a conversation with a politician; the party line always comes first.

But he also says he had very happy moments when he was sailing and travelling. He still has New Leaf, which is currently moored in Dublin, but which he will be taking around to Cork soon. "And I do occasionally look at the boat and wonder about another trip," he confesses, looking out the window and smiling at the idea of setting sail again.