Paul McKenna is an exquisitely groomed man with a penchant, I have heard, for Armani suits. But no, he corrects me: “This is Brioni.” Brioni, Brioni? My mind momentarily blanks. “James Bond wears Brioni,” he says helpfully. As an unhappy schoolboy, it transpires, McKenna used to lock himself in his bedroom and fantasise about becoming a 007-style secret agent. Instead, he ended up as a hypnotist and the nation’s leading motivation guru. Today, thanks to the television shows, the blockbuster books and the sell-out seminars, he is a multi-millionaire who can buy Brioni suits like Bond buys Martinis.

McKenna loves his “externals” – his three watches (Rolex Daytona, Cartier Panther and a Jaeger LeCoultre); his four cars (Bentley Arnage, Ferrari 575, Range Rover Sport and a Jeep wagon) and his luxury bachelor pad in the heart of Kensington, which, with its leather sofas and soothing black and cream decor, could easily double as a Cubby Broccoli-inspired film set. He loves them all so much that it seems too cruel to tell him that he is never going to look like Daniel Craig. His eyes are truly mesmerising, but the frame is too slight, the demeanour too twitchy. I try mentally stripping him of the Brioni and placing him in Craig’s cute blue swimming trunks. It’s a no-go.

No matter. Because of one thing I am sure. The prospect of interviewing McKenna is infinitely more seductive than an encounter with Craig or Brosnan or all the Bonds combined. In many ways it feels like my most enticing assignment ever. Actors can be achingly one-sided, but McKenna is promising a two-way thing. I talk to him about the theories expounded in his latest book; he tries out his theories on me. The book is called I Can Make You Rich. It could be my lucky day.

I meet McKenna in the office that occupies the ground floor of his mews house. From the outside, it’s nondescript; inside, however, there’s a shrine-like aura. A life-size cutout of the boss stands to the side of a sofa, and posters, magazine covers and book jackets adorn every wall. “I’m an ego-maniac, obviously,” he chuckles as we trot through a side door and up, through his private quarters, to a roof terrace.

McKenna may be a showman, but he’s no faker. Last year, my friend, a committed smoker, spent an hour in this very building, undergoing some mental reprogramming with McKenna. She hasn’t had a cigarette since. Another previously yo-yo-dieting acquaintance credits I Can Make You Thin, the book that sets out McKenna’s weight-loss system (1 million copies sold so far) for ending her battle with binge-eating. She no longer obsesses about food and hasn’t stepped on the bathroom scales for months, but her drop in dress size from 14 to 12 speaks for itself.

The opening salvo of McKenna’s latest opus is: “You are about to become rich!” and the optimistic, open-minded side of me so wants to believe him. But, but, but. It’s one, very noble, thing to help people to quit smoking (I speak as an ex-smoker converted by McKenna’s hypnotherapy arch-rival, the late Allen Carr), and there is a certain feasible logic in the idea that you might enable people to become slimmer by persuading them to view themselves through an alternative lens. It is quite another to suggest that you can turn everyone into a Sir Richard Branson, Dame Anita Roddick, Stelios Haji-Ioannou, or any other of the super-rich role models who have contributed to his book. Common sense says it can’t be done – and yet, secretly, irrationally, I am very much hoping that McKenna is going to convince me otherwise.

I’m not poor, I tell him, but by no stretch am I as wealthy as I would like. He runs through a set of quick-fire questions. “Do you do the job you like?” he asks. “Love your husband? Enjoy your children? Do you eat well, dress the way you want, have good friends? F*** me, you’re rich,” he declares, slapping his thigh with a flourish.

Oh dear. I had predicted as much. The money-can’t-buy-you-happiness, you-are-richer-than-you-think-you-are line. “Maybe money is not that important to you,” he suggests. But it is! I don’t mean to sound greedy, but, like anyone, I would like to not be overdrawn at the end of every month, to go on the school shoe-shopping expedition without wincing, and to believe that one day, I really will be mortgage-free.

McKenna adopts a sympathetic, I’ve-been-there tone. For many years, he says, he observed plenty of people with lots of money who were not more intelligent, harder working or necessarily luckier than himself “and I used to wonder, ‘what the heck is it that they are doing?’ ” But that was before he discovered neuro-linguistic programming (NLP), the positive thinking and visualisation philosophy that now underpins all his work. There are several strands to NLP. One is mind-reprogramming – the unpacking and rebuilding of belief systems to cure yourself of attitudes ingrained from your upbringing. Another is behavioural modelling – if someone has a skill you want to master, you “model” it, so that you can learn to do what they do, only in a fraction of the time that it took them.

In conceiving I Can Make You Rich, McKenna harnessed these techniques with his observations gleaned from interviews with several fabulously wealthy subjects. His aim, he says, was to deconstruct the pictures and sounds in their heads and get to the core of their mindsets. Sol Kerzner, the hotel magnate, explained how he visualised every aspect of every new complex he builds; retailer Sir Philip Green revealed how he “downsides” as well as “upsides” every deal in his head before he signs and Branson, who has written the foreword, confided that he goes through the mental process of placing images of any unsuccessful projects behind his back and walking away from them.

Rich people are obsessive thinkers, tenacious geniuses and passionate about everything they do, McKenna concludes. No surprises there. More interesting is his counter-assessment of what keeps poor people poor.

“This country is riddled with vindictive envy towards the rich,” he sighs. “It is appalling. You hear terms like ‘filthy rich’ all the time. Imagine if someone said, ‘filthy black, filthy Jew, filthy Indian’. We would be horrified. The wealthy are the last bastion of people that we can publicly have a pop at. I’ve felt it too, I’ve sat and watched footballers and movie stars and thought, I can’t believe these bastards are being paid all this money.

“But then I discovered that if you envy the rich, you will find it harder to become rich yourself. And if you do become rich, you will hate yourself at some level. So now, I think if footballers can hold people’s attention and deliver something that people want to pay for, good for them.”

And good for him, too, presumably, because McKenna, a builder’s son from Enfield, North London, whose scant school qualifications include a Grade 5 CSE in maths, is now, at 43, very rich indeed. Just how much is he worth? “I’ve never said, but I think it’s fair to say I’m a wealthy man.” I’ve read £10 million. “It’s a lot more than that.” In his book, he observes that many people are more prepared to talk about their sex lives than their finances. “I did say that, but I don’t talk about either actually,” he says, his mellifluous voice developing a slight so-there edge. “And if you ask me how many girls I’ve slept with, I’m not going to tell you!”

As a boy, McKenna, the elder of two sons, recalls watching the fluctuating fortunes of his father’s construction business and “deciding that I didn’t ever want to have to worry about money”. He also recalls telling his mother, a cookery teacher who still works as an education adviser, that he was going to be famous. He flirted with rock stardom, but by the age of 12 had set his heart on being a DJ like his hero Kenny Everett.

McKenna liked his parents, but hated school. Specifically, he hated the Catholic comprehensive run by Jesuit priests that he attended, a place “run on a mindset of guilt, where everyone was constantly put down and made to feel not good enough”.

He quotes one of his school reports which said: “If he carries on like this, he’ll never amount to anything.” When, several years later, he published his first book, he sent a copy to his English teacher with “F*** you” written inside the front cover. “Very childish, I know, but also very satisfying.”

His teachers’ academic forecast may have been spot-on – but it took no account of McKenna’s phenomenal drive. He became a successful DJ, making his way from Top-shop, via Radio Caroline, Chiltern and Capital, to Radio 1. He also moonlighted as a hypnotist, having been entranced by a fellow practitioner he interviewed on one of his radio shows. In his early 20s, he wrote a note to his then boss saying he would be a millionaire by the age of 30 – a prophesy he fulfilled. “Outwardly, I had it all, but inwardly, I was geeky, nerdy, rubbish, a loser and I didn’t want to be found out. A lot of high achievers succeed out of lack of self worth, out of the determination to show everyone. The problem with that is, while it is a great motivator, you never get to enjoy it.

“I wasn’t some emotional cripple. I was making it work. But there are many complexities to our psyche, so part of me was happy and successful, but another part was eaten away by that feeling that nothing was quite enough. Some people develop an addiction. They can’t sleep with enough girls, score enough goals, close enough deals. When you get to that point, you are out of control. Until a few years ago, I wasn’t the major shareholder in my feelings. I thought I needed a bigger house, more cars, more beautiful girls, more money, more fame. Then I tipped the other way. I realised I had everything I wanted and began to make peace with the aspects of myself I hadn’t wanted to admit to.”

This is the phase he has referred to in his earlier books as “the healing of the inner nerd”. It would best suit his zippy style if it had happened in a Damascene moment, but in real life, there’s always a more intricate narrative.

By the early 1990s, McKenna had quit DJing to become a full-time hypnotist. His television show The Hypnotic World of Paul McKenna was attracting 12 million viewers and he was further embellishing his income with lucrative live shows around the country. One night, in High Wycombe, a guy called Christopher Gates came on the stage, danced like a ballerina and they had a few laughs. A few days later his girlfriend called to say he was behaving weirdly. Gates was diagnosed with schizophrenia and McKenna was accused of making him that way. It was four years before McKenna cleared his name in the High Court. “Everything was up for grabs. If I had lost, I would have been bankrupt and made to look like someone who cynically profited from making fools of people. Let’s not forget that ten years ago, that was considered a bad thing. Today I would be hailed as a contributor to reality television!”

In that bleak time, as he gazed over the edge of the abyss, he began working with Richard Bandler, the Californian co-founder of NLP. McKenna was already an NLP-convert – “I’d read the books, seen the videos” – and when, in 1994, he heard that Bandler was giving a seminar in London, he pursued him. They started running seminars together and Bandler, a former Hells Angel and cocaine abuser, became his saviour and his mentor, helping him to reprogramme his mind, banishing the negative thoughts and creating the blueprint for the life he now leads.

His conversion also came, he says, from the gradual realisation that “the truly wealthy don’t do envy. They know that resentment is a dumb place to be.” By truly wealthy he means “rich thinkers” – people who have money, but are also happy in themselves. “Poor thinkers, on the other hand, may have big houses and wear fancy clothes, but their heads are filled with fears about the future and mistrust of those around them.”

McKenna used to be a poor thinker, now he’s mostly a rich thinker. He still loves his externals, “but I don’t get my self-esteem from driving my Bentley. I’ve realised I don’t need any of those things to make me happier. I quite like myself as I am.”

Professionally, he couldn’t be in a better place. He’s working on an interactive self-improvement television show with an American producer. He’s also contemplating an education book, I Can Make Your Kids Brighter. (He made up for his own lacklustre education several years ago with a PhD from business school IMCA – his thesis on human behaviour became his bestselling book Change Your Life in 7 Days.) He’s got bigplans and when he talks about them, his speech is like his prose – peppered with punchy exclamation marks.

About his personal life though, he is less gung-ho. “I’ve had a few challenges recently,” he concedes. McKenna used to talk in interviews about wanting to get married and have children, but it hasn’t happened. He says he realised some time ago that he was a commitment-phobe. “I have managed long relationships. But I’ve been hurt and I don’t care what anyone says, it’s rough when you get your heart broken.”

He tells how Richard Bandler helped him to recover with a technique developed originally for abused women. “Artificially you drive the brain through a threshold so that you just can’t go back to that person. I was in a relationship with someone who kept wanting to leave and then come back. I didn’t know where I was. So I used Richard’s technique and it worked amazingly. The next time she called me it was like speaking talking to someone I knew a long time ago.” He has a steady girlfriend now – Niki Roe, an animal behaviourist. They’ve been together a year. Is that a long time for him? “Hell yes. A week would have been a long time once.” So is he in love? “I don’t really want to go into all that, if that’s OK,” he says hesitantly. I tell him he sounds like Prince Charles. “I’m sorry. I’m told I’m cold and unemotional. Possibly I am. Maybe this is all I am capable of. Who knows?”

McKenna replaces his glasses and leans forward, signalling that it is time for the interview to end and for the therapy session to begin. He wants to know if I have already tried some of the exercises in the book. I only had a day to read it, but I was taken by his idea of a wealth thermostat. This is a simple mental device based on the assumption that most of us put an unconscious “upper limit” on the value of what we do. He cites the example of his friend the corporate trainer who was charging £1,200 a day and feared he would never make as much money as he needed. McKenna told him to add a zero to his next proposal. His friend said he couldn’t possibly, but he did double his fee, and then he doubled it again until he was regularly receiving £5,000 a day.

I told my editor about this and suggested she might like to add a zero to my fee for this interview. She assumed, naturally, that I was joking. That, I tell McKenna, is my problem. I’m pathetic about money. I know that I could be maximising my financial efficiency, but I’m a hostage to a market system. He starts tapping his toe and machine gunning questions. If I had all the money in the world, what would I change? How would I do things differently? Two minutes later, I find I am confiding in him ideas about writing books that perhaps I have not even admitted to myself. “Gre-aaaa-t,” he twangs. “OK. I am going to suggest to you, right now, and we are not even half way through this, that you could do that tomorrow. You already have all the qualifications. You could contact all the top literary agents right now. Right this minute.”

He’s so enthused, so euphoric, that I can’t bear to bring him down. But he’s also one step ahead of me. “Fear of failure. Fear of rejection. I know. Procrastinators aren’t lazy. They’re scared.” He tells me about a guy he used to envy. “He wasn’t particularly handsome, but he dated more girls than anyone else. I studied him for a while and I figured out that because he was thick-skinned, he asked more girls out than anyone else. And I thought if I up the number of girls I ask out, the down side is that I might be told to F-off more, but the upside is that I might meet the person of my dreams.”

He sounds utterly convincing, because, very cleverly, he’s homed in on his own emotional weak spot. He says he’s going to give me the number of his agent “and he’s a really nice man by the way”. But before that, he’s got a few tricks left. “Give me your hands and close your eyes.” We run through some visualisation exercises that involve amplifying good feelings and shrinking the bad. He tells me to squeeze the thumb and middle finger on my right hand and think of a feelgood memory. “Got it? Yeah, great, beautiful.” His mobile phone rings. “I’ve been held up. I’ll be with you by 7,” he tells the caller. And to me: “I hate being late, but I also hate leaving a job half done.” I’m squeezing my fingers and thumbs and keeping my eyes firmly shut. He’s stomping his foot now and talking excessively fast. “Imagine taking that feeling home with you, imagine waking up with it tomorrow, imagine having it next week, next month. Feel good? OK, open your eyes.”

We both collapse with laughter. Me because I feel faintly ridiculous. And him? “I love my life,” he hoots. “As soon as I saw you, I could tell that your joy levels needed to go up. And if I am going to make you feel good, I have to go there, too. So yes. Absolutely. It’s been an intense pleasure.”

Postscript: It is now three weeks since I met McKenna. In the intervening period I have been on holiday and consequently returned to a larger than usual overdraft. The cat’s just been run over, necessitating an unexpected £600 vet’s bill. The orthodontist has informed me that my son’s crooked teeth are no longer deemed severe enough to warrant NHS treatment (as they would have done before the rules changed 18 months ago) and I must therefore find another £2,500. I’m in financial freefall and should be unbearably morose. But I’ve been squeezing my fingers and thumbs and have listened several times to McKenna’s CD. It’s not exactly hypnotic, but it offers 25 minutes of deep relaxation.

Those who want to be seriously rich may also work their way assiduously through his exercises and I have no doubt that they will be financially better off at the end of it. I haven’t, partly because I’ve been too busy, but more honestly because, as McKenna so astutely observed within two minutes of assessing my situation, having vast amounts of money isn’t that important to me. “If it was, you’d do something about it.”

Grudgingly, but also appreciatively, I have to admit he’s right. Being rich is ultimately about raising those joy levels. We had a lovely family holiday. The cat lived. The bank will wait. Life’s not so bad.

I Can Make You Rich, by Paul McKenna, published on September 11 by Transworld Publishers, £18.99. Available for £17.09 from Times BooksFirst, 0870 1608080