Interested? There’s a 78-year-old man I know who can do it. But before you get excited, you’d better have a spare $15,000 (#163;10,000) to hand for what is undoubtedly the most expensive but, allegedly, the most effective language course in the world. Taught, if you want to be hyperbolic about it, by the most mysterious and intriguing language teacher you’re ever likely to encounter.

For the past 30 years, Michel Thomas has been a closely guarded secret to just about everybody but the rich and famous. When Grace Kelly became engaged to Prince Rainier, it was Thomas who taught her French - in three days. When Truffaut had to learn English in a hurry, when Woody Allen and Bob Dylan decided to tackle French, when octogenarian and squillionaire industrialist Armand Hammer wanted to learn “proper” Russian, they sent for Thomas, sat with him for three eight-hour days and learned what they set out to learn. And they remained devoted friends with him for the rest of their lives.

It all sounds outrageous. How can this man claim to teach in a few days what others only manage in years? Certainly Thomas has got up the noses of several top American universities’ languages departments, including UCLA. Meeting him, you can see why. His alleged personal magnetism does not stretch to diplomacy when it comes to any other way of teaching languages but his own. Immersion teaching? “I coined the phrase many years ago. But it’s drowning, not immersion. It can only work on a primitive level except for children under the age of eight. ”

Traditional language teaching in schools? “It’s a nonsense when language teachers tell students they have failed and that you have to be gifted to learn a language. The responsibility for learning and remembering is and should be with the teacher - never the student. If any student does not remember something, it’s the fault of the teacher, not the student.” The British education system in general? “If Gillian Shephard were to ring me tomorrow, I would be very happy to talk to her and share my methods and help solve problems. I’m not holding back anything.”

In the event that Mrs Shephard doesn’t get around to ringing Thomas, we’ll all be able to glean something of his methodology in a BBC Education documentary, The Knowledge: The Language Master being screened on BBC2 in the summer term.

Producer Nigel Levy, who first heard about Thomas from a newspaper article while on holiday in Israel, was set a challenge when he first approached the language teacher about filming him. “He offered me one-to-one Spanish tuition for three days, without payment. If I learned Spanish in that time, he said I could go ahead and do the film. If not, then we’d forget it.” Levy, a self-acknowledge d dunce when it comes to Spanish (he scraped by with 17 per cent at secondary school), went for it.

He sat with Thomas for three-and-a-half days, followed up by his own independent study, which consisted of a week’s reading of Spanish newspapers and magazines to top up vocabulary; Thomas’s course does not focus on words so much as structures. When Levy was tested by the Cervantes Institute in London afterwards, he was told that his spoken Spanish was equivalent to one year’s studying. “It’s not miraculous,” insists Levy. “The way Michel Thomas teaches allows you to understand grammar and structure after three days.”

How? Thomas explains: “The first phase in my course, whether it’s one-to-one or in a classroom, is the acquisition of the solid, comprehensive knowledge of the entire structure of the target language - grammar, syntax, mechanics and practical and functional vocabulary - so that you know how to formulate your thoughts. All this is achieved without memorising or learning by rote or drilling or textbooks or taking notes or homework. Not even mental homework is allowed. Visual aids aren’t allowed either, because they interfere with learning. It’s important not to review mentally.” The first phase is delivered in the student’s language. The second phase, geared to the student’s particular social, personal, professional and academic needs, is carried out in the target language and is aimed at proficiency in the language.

That’s great, but how do you learn if you’re not allowed to use the traditional methods? “I’ll explain a concept in a simple, easily comprehensible way and immediately apply it in sentences. Then I’ll ask them for questions and for examples of how to do what I have done.” Levy adds: “He deconstructs language so that everything locks into everything else and it makes perfect sense. By the second day, I could say: ‘I would like to see you but I’ve had a hard time understanding what you’ve said.’”

But despite his simplistic explanations, the fact is that this film is the first time that Michel Thomas has agreed to go public. He has kept his language teaching methods a closely guarded secret, causing outrage and suspicion among the academic community in the United States, who can’t understand why he doesn’t want to share. For Thomas, it’s quite simple: “I don’t have any reason to trust anybody who asks me to show them what I have. It invites plagiarism, and plagiarism goes against my principles.”

To understand his position, it helps to look at where he has come from. He admits that “language has been very useful to me”. While he deliberately shrouds his Jewish eastern European origins in mystery, the pseudonymous Thomas will reveal that he grew up in France and was studying in Vienna when Hitler annexed Austria.

His wartime experiences almost defy belief. In the course of six years, he was an intelligence officer with the French Resistance, an officer in the US army with combat troops in France and Germany as well as with US counter-intelligence, the sole survivor of the Levernet concentration camp in France and among the US troops who liberated Dachau. He posed as a German and as a Frenchman when it was expedient, thereby saving his life through his fluency in languages.

Today, he speaks 11 languages but regards himself as fluent in only five. As well as making a career for himself as language teacher to the stars and running language schools in Los Angeles and New York, he has worked with inner-city schools to help raise children’s self-esteem by making them feel good about learning a language.

When the Los Angeles school district was at the end of its tether after the Watts riots in 1965, Thomas spent two weeks in a school practically destroyed by fire and looting, to calm things down. “I went in to demonstrate what can be done when you get children wanting to learn. The teacher was afraid the students would attack me. By the third day, I could hear a pin drop and the worst threat I could deliver to them was sending them out of the room. They didn’t want to leave.” After two weeks, they were speaking French.

On his visit to Britain last summer, the film crew followed Thomas into City and Islington Sixth Form Centre in London to document his techniques with a small group of mainly non-academic general national vocational qualification business studies students.

One girl in the group had been told by a previous teacher that she had no aptitude and shouldn’t waste her time coming to French classes. After five nine-hour sessions, she and the others were speaking, reading and writing French. Another student, Maria Pinnock, 18, said: “I’ve been doing French for five years and have only learned basic stuff. But with Michel, you can stand up on your own two feet.” Twenty-year-old Darminder Singh put it this way: “If you’ve got the ingredients, you can cook what you want. Once you’ve got the structure, you can do anything. ”