Repeat after me...

Paul McKenna’s official statement says that he is delighted, but Britain’s leading hypnotist and self-help guru, whose books sell by the zillion, doesn’t sound especially delighted to me. “To tell you the truth,” he says, “I am worn out.”

We are talking just minutes after he learnt that he had won his libel action against the Daily Mirror and Victor Lewis-Smith, its former columnist. In a series of articles written between 1997 and 2003, Lewis-Smith alleged that McKenna’s claim to hold a PhD from a US university was fraudulent because his degree had been obtained by post and merely in return for the payment of money.

The institution that granted McKenna’s PhD did indeed turn out to be dodgy: its former president, a convicted fraudster, admitted to the FBI that it wasn’t properly accredited. But McKenna has said all along that he didn’t know that at the time. He worked for more than 500 hours on a 70,000 word thesis that subsequently became a bestselling book, Change Your Life in 7 Days.

He originally asked the Mirror for a modest correction but the paper refused and Lewis-Smith repeated the issue again and again -so it went to court. “Whereupon the Mirror’s lawyer threatened to ruin me personally and financially,” says McKenna, who has a mews house in Kensington, west London, buys and sells cars from his rock star mates and seems always to be accompanied by a group of glamorous women.

On Friday Mr Justice Eady came down clearly in favour of the hypnotist -“Mr McKenna was not, in my judgment, dishonest,” the judge said -but it may be something of a phyrric victory. McKenna is liable for a big share of the £ 1.5m court costs and may win damages of only £ 20,000.

I can understand why he was angry at the slur. What I don’t understand is why a man who already commanded vast television audiences -and who left school with two O-levels, one CSE and an A-level in art -would want a PhD anyway.

“I wanted to do this because a PhD is a contribution to the scientific community, or the community at large,” McKenna says. “I had amassed about 10 years of research and I wanted to make that into a formally published thesis.”

Why LaSalle University in Mandeville, Louisiana; surely there are more prestigious institutions closer to home? “I chose LaSalle because it was the only place I found that did a PhD programme in hypnotherapy. I didn’t want to do conventional psychology. I still wouldn’t. That doesn’t really interest me, but hypnotherapy does.”

Hypnotherapists believe that patients under trance are more receptive than otherwise to all kinds of treatment, particularly for anxiety, stress and addiction. McKenna, 43, went on to get another, absolutely legitimate, PhD in 2003. It has an impressively academic title: “The effect of fixed action patterns and neuro- linguistic programming in determining outcomes in human behaviour”. He says that half a million people have bought copies of his thesis.

Entering into the spirit of academic chit-chat, I ask McKenna if he has come across the pioneering hypnosis unit at University College London led by David Oakley, the brilliant professor. This is the only centre that offers specialist training in hypnosis studies to be validated by a British university. To my surprise, McKenna says that he has never heard of it.

Meeting McKenna for the first time a few years ago, I had found him smaller than expected and surprisingly downbeat. Not negative, but quiet and measured – certainly not the bouncy character that you would expect from his stage act.

He first became interested in hypnosis while working as a disc jockey. After being hypnotised himself, he set about learning the techniques and quickly became extremely successful.

His TV shows, in which ordinary people did extraordinary things under his suggestion, attracted millions of viewers. But he lost his enthusiasm for stage hypnosis after he was sued by a man who claimed -falsely -that McKenna had caused him to become schizophrenic.

Since then he has become better known for his extraordinarily successful self help books, which have netted him the largest fee so far for works of non-fiction, and for his training sessions with executives, athletes and celebrities. He recently helped Little Britain’s David Walliams to set one of the fastest speeds for swimming the Channel.

It is while talking about this that McKenna lights up for the first time. “I am shallow,” he says with unprecedented cheerfulness, “and if a well known person asks to come to see me, I usually say yes.”

How did he help Walliams? “With athletes it depends on the sport, but you can make people think they are stronger. David had to overcome fatigue and pain, so I taught him techniques to release endorphins, to think of positive things.

“And I taught him how to distort time -we can make people think time is passing faster or slower -because he was going to be in the water for a long time.”

(McKenna has previously done the opposite for Formula One drivers, teaching them to make microseconds pass more slowly.)

As well as helping people to change their lives in seven days, McKenna’s books have tackled weight loss, self-confidence and giving up smoking. Together with the seminars and the work with private clients, they have earned him a fortune. His turnover is estimated at £ 2.5m a year.

“Making money was never my primary intention,” he says. “If I was interested in that I would be in banking or oil, like a lot of my friends. Often my publishers suggest a book and I say, I don’t really feel motivated to do that. Money is a factor, clearly. But there are an awful lot of unhappy rich people. Happiness is a neurochemical event in the brain, it’s not measurable directly in relation to money.”

Victor Frankl, the Austrian psychiatrist and Holocaust survivor, believed that the cornerstone of good mental health is having a purpose. McKenna believes that too: “It’s essential for human beings to have a clear mission.”

Does he have a mission? “I do. It doesn’t really fit neatly into a sentence, but overall it’s to make a significant contribution to humanity in the area of psychology.”

He will continue to do self-help books in areas where he thinks his techniques can be of use: “Sometimes that doesn’t mean writing for the greatest number of people.

“My book on overcoming emotional pain at the end of a relationship has not been an amazing seller, but people have said that they were in utter despair and this brought them back from the brink.”

Physicians are notoriously bad at healing themselves. Are hypnotherapists any better? Does Paul McKenna get good results on Paul McKenna? If so, how does he decide what needs fixing? “How do I decide?” He ponders the question for a moment: “If I feel unhappy, I make a change.”

I ask if he is angry with Lewis-Smith -and, if so, whether that anger is something he intends to tackle. “I was angry, not so much now because it’s in the past. I felt misrepresented, not just once but eight times. And it didn’t only hurt my reputation but the people who work for me.”

More generally, McKenna accepts that the skills that have helped others may not always help him: “Some things I can fix and some things I can’t. I’m a work in progress.”

Change Your Life in 7 Days -the book based on that controversial 70,000-word thesis -“isn’t meant to solve everyone’s problems. I don’t think you can do that. Problems are what help you to learn and grow.”