JOHN SEYMOUR was an environmentalist, activist, broadcaster, farmer and futurist whose numerous publications — he wrote or co-wrote nearly 40 books and many articles — were the chief inspirations of the organic homesteading movement which burgeoned in the 1960s and 1970s. His most famous work, The Complete Book of Self-Sufficiency (1975), sold more than a million copies and was translated into 20 languages. It was, and still is, the bible of the “good life ” movement. The most recent reprint, in 2003, was subtitled: “The classic guide for realists and dreamers”.

John Seymour was born in 1914 in London. His mother remarried when his father died, and the family moved to Frinton-on-Sea. After prep schools in England and Geneva, he studied for three years at Wye Agricultural College in Kent, but failed to gain a diploma — the only failure in his class.

At 20, declining the invitation to follow his millionaire stepfather in his chewing-gum business, Seymour went to South Africa under the auspices of the Settlers’ Memorial Association which was seeking to increase English immigration there. After a short spell of training, he found a job on a farm with 200,000 sheep. He moved to manage a farm farther north, and then became a deckhand on a fishing boat in Walvis Bay. There followed a spell working in a copper mine in Northern Rhodesia (now Zambia) before he joined the Northern Rhodesia Veterinary Service.

On the outbreak of the Second World War he joined the King’s African Rifles and fought against the Italians in Ethiopia. (One of the battalion cooks was Idi Amin, the future tyrant of Uganda.)

The battalion was posted first to Ceylon (now Sri Lanka) where Seymour, a commissioned officer, led his own mortar platoon, and then to Burma where his hearing was damaged by mortar fire. Having learnt to respect the fighting qualities of the Japanese soldiers, he was moved to outrage when he heard the news of the bombing of Hiroshima. Even in his old age he declared, with characteristic vehemence: “I was disgusted about it. Bombing civilians, women and little children. I cannot forgive the Allies for it. I thought it was a sordid, low-down thing to do and I’ve never got over it. We had the measure of the Japanese, we were beating them. We didn’t need to do a filthy thing like that.”

Once back in Britain Seymour lived and worked on a sailing barge before becoming a War Agricultural Officer, a civil servant who organised farm jobs for thousands of German PoWs. After a three-year spell, he found a niche doing 15-minute radio broadcasts for the BBC Home Service. He would simply talk about subjects which interested him. On the strength of these, the BBC sent him on a trip to India, and his radio talks about his encounters led to a book offer from a publisher. This opened up the possibility of a career as an author, which could be combined with his growing ambition to become a smallholder and to learn how to become self-sufficient. By then married to Sally, a potter, Seymour established himself on a few acres in Suffolk, and from this experience emerged one of his first books, The Fat of the Land (1961). His books, like his frequent broadcasts, covered his early experiences as a global traveller, and as a farmer, miner, sailor, infantry officer, civil servant, veterinary officer and fisherman. His success as a writer was based partly on the vast range of his experiences and partly on his gift for simple, straightforward expression, especially in complex technical matters, combined with a bubbling sense of humour.

This combination prompted two young publishers called Christopher Dorling and Peter Kindersley to commission his magnum opus, The Complete Book of Self-Sufficiency. In it Seymour briskly explained everything from making compost and bread to butchering a pig. Appearing during the economic slump in the aftermath of the 1973 oil crisis, the book was a phenomenal success worldwide and brought Seymour international recognition as the guru of the self-sufficiency movement. It also instantly established Dorling Kindersley as a publishing-house of repute.

By this time Seymour had moved from East Anglia to a larger smallholding in Pembrokeshire, where he juggled the demands of farming, writing and celebrity with indomitable energy. Not the least remarkable of his writings was his last book, a little-noticed novel, Retrieved from the Future, which anticipated another English civil war after the collapse of oil supplies and the pricking of the global economic bubble.

Seymour wrote and campaigned against many evils, including nuclear weapons and the Vietnam War, and his last campaign was against genetically modified crops, which he regarded as little short of satanic.

In the 1980s he moved from Wales to Co Wexford, in the Irish Republic, and he would cheerfully recount how experimental GM sugar beet planted by the giant American agrichemical company Monsanto near his farm was repeatedly dug up in night forays until the company was compelled to abandon the site. Seymour declared that it was all the work of the fairies; when challenged that fairies do not leave muddy bootprints, he said that they must have been in disguise. This did not persuade the judge, who imposed £30 costs — not, however, the £16,000 demanded by Monsanto.

If, despite the range and quantity of his writing, Seymour’s fame was mostly confined to environmentalist circles and followers of sustainability movements, that was largely because he was not remotely interested in the trappings of fame. He argued that life was meant to be lived and loved, and he was far more likely to be found dancing a jig on a table in an Irish pub than giving a solemn lecture in a crowded academic hall.

He had a great love of informal social occasions where he would often lead the company with songs, frequently of his own composition — a streak which found expression in yet another book, a collection of doggerel entitled Playing It For Laughs. The cover contained a warning to parents that it was not to be read by anyone under the age of 84½ and announced that the author was “completely prejudiced, utterly biased and without any sense of moderation or proportion ”. A characteristic example concerned an old man of the sea “who sat on a chorus girl’s knee,/ His wife said she’d divorce him/ But only to force him/ To get off her and come home for his tea”.

While his more important books, such as Far From Paradise and Blueprint for a Green Planet, focused on the environment, all of them expressed disquiet about the drift of events as they affected the countryside and the quality of people’s lives.

Although Seymour married three times, he retained the affection of all his wives and their six children. He died on the Welsh farmstead of one of his daughters and was buried on his family’s land, wrapped in blankets made of wool from his own sheep.

John Seymour’s first marriage was to Sally Medworth in 1954. He was subsequently married to Frances Hurdle and finally Vicky Moller. He is survived by his wife and former wives, and by six children.

John Seymour, farmer, writer and environmentalist, was born on June 12, 1914. He died on September 14, 2004, aged 90.