Fine dining for children is spreading peanut butter and strawberry jam to make a sickly sarnie, then boasting to mummy it tastes fantastic. Heston Blumenthal has taken this grand tradition further, developing something called molecular and physical gastronomy, resulting in lots of apparently clever folk shovelling down his snail porridge. Yet rather than being closed down by health and safety, Blumenthal has just been voted best chef in the world.

The history of western civilisation might pinpoint our decline to the opening of the Fat Duck in Bray. For Blumenthal’s restaurant suggests we have grown too bored to eat; only smoked bacon and egg ice cream could excite jaded palates. Restaurant critics have lapped it up. The question is: were the chubby oiks sent by a tabloid to evaluate the Fat Duck’s 16-course tasting menu — £97.50 a head — entirely stupid when they declared they would rather munch Big Macs?

In short, I was sceptical setting off to the Berkshire village of Bray to meet Dr Strangefood. If Jamie Oliver can effect government U-turns and Gordon Ramsay can exhibit an ego bigger than a four-oven Aga, just how insufferable will be the owner of the most celebrated nosh house this side of Mars? The first surprise is the restaurant: a tiny terraced cottage, where you might pack granny off. The second is Blumenthal himself: shaven-headed and shy, he looks like a down-table carrot-chopper, not the “genius” that invented rocket salad science.

He had been up until 4am celebrating but is cheery for our 9am interview. He looks younger than 38 — you might mistake him for a professional footballer with a brain — and seems free of histrionics. The night of his great triumph he was told the dishwasher had conked out. “It is only 10 years ago I started, and I was sleeping in dirty linen,” he recalls. “Before that I was a repo man (debt collector) and then, for eight years, an accountant.”

Now he has a laboratory across the road bristling with men in white coats and a female PhD research fellow. He talks excitedly about his new drink that is cold one side of the glass, hot the other; you expect Q to appear with an exploding snail.

This interest in the scientific aspect of food seems surprising, not least because his single A-level is in art. It stems from a trip to a food lab in Geneva, which he made out of curiosity after he’d set up his restaurant. He was fascinated: it reminded him of Willy Wonka and the Chocolate Factory. There, he learnt that certain chemicals in liver can also be found in jasmine, so he tried combining the two.

He started staying up at night, reading scientific journals that broke down foods to the chemical elements, discovering that seemingly very different foods actually shared qualities. He is now following Jamie Oliver into education and has devised a lesson — “kitchen chemistry” — with the Royal Society of Chemistry to be sent to every school in Britain. It will teach pupils how to make Blumenthal’s infamous ice cream using his favourite ingredient — liquid nitrogen. He hopes this will provide the intellectual meat to Oliver’s starter in the war on Turkey Twizzlers.

Despite his remarkable life turns, Blumenthal seems largely unchanged. Did he find it hard repossessing people’s gear? “No, I was all right at it, actually.” I meant morally. “Oh, well it was only companies. I had an interesting altercation in Dudley. It was an Indian who denied he owed the money. He then made a call and half a dozen of his mates turned up. I gave up with the meagre wage I was on.”

Having abandoned “credit control”, he toiled as an accountant for his father’s leasing company. His father was from Zimbabwe — though from English stock — but returned to Blighty as the troubles began there and married Heston’s English mother. She could cook, he says, but most nights it was fish fingers rather than anything gastronomic.

The family started out in a one- bedroomed flat in London’s Shepherd’s Bush, moving to Marlow, Buckinghamshire, when Blumenthal Sr’s business took off. When Blumenthal was 16, they splashed out for the first time and took a holiday in Provence, eating at a three-star Michelin restaurant. It was not only a memorable holiday, but the start of an obsession.

“It was my first time abroad and none of us had eaten at a restaurant with one star, let alone three. The setting was magical, by cliffs, with olive groves, lavender and the crunch of the gravel. And a sommelier with the obligatory handlebar moustache; I can remember it so vividly,” he says, eyes sparkling. “I knew instantly it was what I wanted to do.”

So Blumenthal pored over cookery books and taught himself French cuisine. “I would try doing a dish 30 different ways. With ice cream, I would analyse why you need eggs, why it needs to be whipped, what is the optimum consistency. Inquisitiveness was a key feature.” Accurate self-analysis, this: his big brown eyes forever dart, taking in details, peering at my notes.

His solitary A-level, he says, owed much to “fortuitous revision the night before” — yet he had a huge hunger for knowledge and was fascinated by the physics of food. Does browning meat retain the juices? What effect does salt in boiling water really have on beans? So he devoured everything written about food science, and was blown away by Nicholas Kurti’s lecture, The Physicist in the Kitchen: “It is a sad reflection on our civilisation that while we measure the temperature in the atmosphere of Venus, we do not know what goes on inside our soufflés.”

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