Luca Turin's theory of smell could revolutionise perfume making but first,as he tells Kate Worsley, he must win over the experts whose noses have been put out of joint

He waves a gleaming blade under my nose and straight away my head fills with a dark odour. It evokes ravens and dowagers, lions' manes and jewelled cabinets, with an acrid charred aftertaste. Suddenly we are not in a poky little office at all, but transfixed in the Doge's Palace in Venice.

The man wielding the paper blade looks suitably gratified at my reaction. Luca Turin, lecturer in biophysics at University College London, proponent of a controversial theory of olfaction and fledgling creator of perfumes has, generously, dipped a smelling strip in a rare amber liquid called Bandit, a 1944 perfume by Piguet.

Smells are what really do it for Luca Turin, anything from Camembert to Chanel No5. He moves in a cloud of perfume trade secrets and big olfactory ideas. His poetic evaluations of 200 top perfumes (smell Mitsouko - think Tiffany lamps! Inhale Shalimar and hear Chopin's Revolutionary Etude!) were published in France in 1992 as Parfums: Le Guide. He tells a mouth-watering tale of the conception of Tommy Hilfiger's 1997 hit fragrance, Tommy Girl - "a stupid low-calorie brief but a giant fragrance" - and yearns for the 1890s, when perfumes were as lush as Brahms: "totally, absolutely wonderful, drop-dead creations. Yeah, gorgeous".

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A few years back Turin's passion for smells resulted in a scientific brainwave. If his theory is right, it has huge implications for the way in which the multimillion pound perfume industry manufactures scents. Smell sets the imagination racing but its mechanisms confound us still. How signals get from the nose to the brain is pretty well understood, how we identify a smell in the first place less so.

Most researchers follow the English scientist J. E. Amoore's 1949 lock and key theory: when a molecule from a smell docks in an appropriately shaped receptor at the top of the human nose it triggers a message to our brain that identifies its smell. Turin, however, is convinced that this is wrong. He argues that a molecule's smell depends mostly on the frequency at which the molecule vibrates rather than on its shape: the revival of an idea first mooted in the 1930s by another English scientist, Malcolm Dyson.

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He has backed up his theory by examining the pair of molecules which stumped the original vibrational theorists. They are mirror images in shape, yet smell entirely different - R-carvone smells of mint, and S-carvone smells of caraway. Turin found a way to alter mint carvone to vibrate in the nose at the same frequency as caraway carvone. The real test is if the altered carvone actually smells of caraway.

Turin took his sniff challenge to Paris, to the ultra-discriminating receptors of three professional French "noses". In a nail-biting sequence for an award-winning BBC television documentary, Code in the Nose, the professionals confirmed that the altered mint carvone did indeed smell of caraway. The Horizon TV cameras lapped up Turin's moment of triumph.

Now he has designed a computer alogrithm that can work out how a human nose will perceive the smell of any molecule. You would think the fragrance companies would jump at it: if his vibrational theory can predict how molecules will smell, it could sweep away the laborious process of trial and error involved in designing new scents. "Rational odorant design'' could dramatically inflate the industry's profit margin.

When the magazine New Scientist followed through on Turin's progress a few weeks ago, none of his theory's numerous opponents had managed to prove him wrong. Yet his attempts to "make some money by predicting smells for the fragrance industry'' have, in his own words, "been an absolute unmitigated ****ing disaster". He chuckles one of his many blithe chuckles.First a one-year consultancy contract with one of the four or five main fragrance companies was not renewed - "too expensive, they said". Then a collaboration with another foundered when he was barred from actually smelling the compounds being tested. That delightful top note of optimism began to wear off.

But Turin has a wisecrack for every disappointment. He prides himself on being an experimentalist, admits to being obsessive, and plays the original disillusioned romantic to the hilt. His anecdotes are peopled with heartbroken perfumers, washed-up Russian scientists washing dishes in Wisconsin and corrupt yet untouchable timeservers. "Mediocrity always finds a way to exploit the system," he explains.

Born in Beirut in 1953 to an Argentinian father who built refugee camps for the United Nations, and a mother who was an Italian designer, Turin was educated at various French schools around Europe. In the 1970s he followed his academic father to UCL to study physiology and biophysics. "Not least because I wouldn't pay any fees. Ten pounds for three years, great value." Then, in what he now feels to be a deeply misguided spirit of nostalgia, he returned to France. After a few golden years as a civil servant in Nice ("I fell in love with Nice") he moved to the Pasteur Institute - "which is to science what the Dorchester is to hotels, everything works". But, too soon, he came across a major scientific scandal, making it impossible for him to go on working in France. He is practically frothing at the memory. "They basically put a gun to my head and said 'Why don't you go to the ends of the earth and shut up'. The French system is fantastically corrupt. It's a scientifically uncivilised country.'' He "fled" to Russia, where his next love affair was with Russian scientists and their "amazingly moral approach to science. I've never met so many true scientists as in Russia". But, inevitably, the situation changed there too. Now, as lecturer at UCL, he is high on Britain - "it's fantastic, the crisis of British science is bull****, it's as buzzy as hell".

Turin has overcome various scientific challenges to his vibration theory, but the fragrance world's commercial pressures are something else. "It's been really very much harder than I thought, and a big disappointment. Nobody wants to lose their job over this, so they haven't been able to work out whether they would get fired for taking me on, or for not taking me on." He adds laconically: "I'm planning that they get fired for not taking me on. But it will take a little longer."

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Admitted to the perfumers' sacred halls, where they have been creating fine perfumes for decades, often with little more than a tenuous grip on basic chemistry, he says he learned some modesty. He is quite stoical. "I don't think they needed me in Paris." Predicting the smell of a particular molecule is one thing, "but predicting what will go with what is of another order of magnitude, much more complex''. He is ploughing on anyway,refining his sales pitch. "Now I know what the tricks are. I couldn't get any worse, that's for sure," he chuckles. What really perks him up, however, is returning to the lab for a hit or two of the fragrances he is art-directing, in his spare time, for a French perfume house, Fragonard. He applies the women's perfume to my right wrist, the men's to my left.

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After all his battles it is a pleasure to find both scents are quietly but sensually harmonious, exhilarating even. Turin says he is aiming for something you can live with at 9.30 in the morning; a sexy smell, but without sweetness. "Sweetness is like cream in sauces; when you run out of ideas you can always chuck in some vanilla. The really interesting thing is to do beautiful things and avoid the obvious. "

Turin's The Perfume Bible, a revised version of Parfums: Le Guide with Michael Edwards, will be published next year. The Fragonard Maison range is launched in Grasse, France in April and in the UK next year.

FAIR AND FOUL FRAGRANCES, ACCORDING TO LUCA TURIN

PERSONAL FAVOURITE

"I wear half a dozen different things depending on how I feel in the morning. A couple of Guerlains - Jicky (1889) and Derby (1984), a de Nicolai perfume, a cheap Rive Gauche (YSL, 1971) imitation I love: Riviera,by Sainsbury's and then I wear the stuff I'm working on.

MEN'S FRAGRANCES

Invariably awful. Most are just dreadful pathetic hairy-chested pieces of nonsense, because they are defined by what doesn't go into them. And because men don't think. When you remove 90 per cent of the perfumer's palette you're stuck with the dregs and then they just mix the dregs and flog 'em to men. It's been boring since the war, with a few great exceptions like Brut (Faberge, 1964). Men used to wear women's perfumes, Jicky was unisex, there was Mouchoir de Monsieur (Guerlain, 1904). But we are coming to the end of what I call the Saddam Hussein school of aftershave. Women will demand that their men smell good rather than awful.

ALL-TIME CLASSIC

The award for integrity goes to Guerlain, which hasn't messed with even its oldest fragrance: Jicky.

MODERN CLASSIC

Chantal Roos and Vera Strubi are two seriously clever and energetic women who have gambled their lives on perfumes like Issey Miyake's Eau d'Issey (1992) and Angel (Thierry Mugler, 1992). Angel was a top-down design. They knew what they wanted, the perfumers delivered, the bottle was great. It could have been a disaster but it was a great success.

MODERN DISASTER

Guerlain's latest Champs-Elysees (1996), was put together to target the young Far East market after the house was bought by the luxury goods conglomerate LVMH. It is modelled on Estee Lauder's Pleasures, a big fresh floral, a really American perfume, with none of the true spirit of Guerlain

PERFUMER OF MERIT

Bandit was created for Piguel in 1944 by the renowned nose - "and well-known dyke" - Germaine Cellier. She also created Vent Vert (P Balmain,1945), Coeur Joie (N Ricci, 1947) and Jolie Madame (P Balmain, 1953). All brutal, angular jazzy perfumes, many with a bitter quinoline base. People have thought of redoing them but leathers just don't sell nowadays.

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NATION OF MERIT

English perfumers, such as John Stephen of the Cotswold Perfumery which does Czech & Speake and Andrew Kobus of BelMay, who did the recent Body Shop perfumes Leap and Oceanus, start out subtle and well-mannered but then surprise you."