Last week I received an email from Euan MacDonald, a 30-year-old former City worker who has motor neurone disease. The email was about Hratch Ogali - the "Mind Instructor" - a healer feted by the tabloids for his "miracle" cures for spinal injuries and paralysis but ostracised by the medical establishment. MacDonald has been his patient for a year. "As this is a progressive condition, results are difficult to measure," MacDonald wrote. "Who knows if I would be better, worse or the same had I not gone to see Hratch? What I can say with certainty is that with Hratch's help I am living without fear."

In Ogali's gleaming yellow studio in Marylebone, just off Harley Street, Alessia is sitting on a bed, wearing a faded Juicy Couture tracksuit. The room is crowded with equipment for physical and motivational therapy: a multi-gym, a climbing frame and a miniature jungle of plants. Diagrams of the skeletal system and the muscular system frown down. Ogali is massaging Alessia's legs, looking, he says, "for active nerves. There is always an active nerve somewhere." He taps her foot with a metal rod and squints. "They start responding." He carries her to a vibrating power plate. "You're getting heavier," he smiles.

"No," Alessia replies.

"Get up and walk," he shouts. But Alessia can't; she was paralysed when the private jet in which she was flying crashed.

"I moved to London because of Hratch," Alessia says. "My family would fly any doctor in the world to Rome to see me. Doctors came from all over Italy, from Cuba and from Germany. My father is a brain surgeon. So after the accident I knew. I didn't need to be told. If you break your spinal cord you don't walk." Hratch grunts, without looking up, "You will walk again."

Ogali used to be a jeweller. Then, he says, "life presented me with a different task". He was born in Syria to Armenian parents but he grew up in Jordan. He came to London in 1962 and met his wife, Tracey, who persuaded him to become a healer. "My experiences were unique in life," he says. "Unusual. I can't identify the first person I healed because people always came to me; always talked about a difficulty of some kind and I always had the advice. Wherever I went this was the case."

He places a walking frame by the bed and tells Alessia to stand. "Go - go - go!" he commands. "Come on! On your toes. Push! Push! Hold tight. Hold tight." She stands. After four weeks of daily treatment, Ogali says, "Alessia is improving. It will all get repaired and these feet will start feeling and we will get you up and walking. How's that? Is that a good plan?"

I watch Ogali "mind instruct" a man with Parkinson's disease. "Back to normal; back to normal," he says as the man struggles to his feet. "Let it be active; let it be alive. Don't let yourself disappear. Think; think." Ogali pauses his incantation, strokes his moustache and stares violently at his patient. "Breathe into your brain through your nose and let it go down your spinal cord. Tell yourself, "I want my life back - not tomorrow, not after lunch, but now!" Fight! Fight! Fight! Don't feel sorry for yourself and don't make yourself weak." Eventually the patient stands, touching Ogali's little finger and they breathe, simultaneously, with triumph. The patient's wife turns to me. "He has a positive attitude and a will now," she says. "Before he met Hratch, he couldn't care less."

The next patient is Florence. She came to England from Nigeria in 1964 to work as a social worker and was diagnosed with the virus GBS in 2000. "It began with weak fingers at half past eight in the morning," she tells me, struggling to enunciate; the virus gifted her with a speech impediment. "By midnight I had lost all feeling."

Ogali's flirtatious incarnation has emerged. He skips out of the consulting room, hugs Florence and demands, "You must get well because I haven't had any proper Nigerian food in this country and you must make it for me." She purses her lips, moodily, at him. "Don't behave like an old woman," he chides and wheels her over to the adapted exercise bike. "Faster! Faster!' he commands. Florence sweats, gasps, and mentions a hip problem. "This stuff with hips; don't make it up," he spits. "You don't need a hip replacement. You haven't done any exercise for four years; that is all that is wrong with your hip. Next week you will stand."

I ask Florence if Ogali's therapies are helpful. "My legs are stronger," she says. "I'm now able to stand. I'm happier and more enthusiastic." What, I ask her, is this mysterious 'mind control'? "'Mind control' is just focusing on what I'm doing. In my sessions with Hratch (which cost £100 an hour), I just say to myself, 'I'm going to do it. I'm going to do it.' I imagine I am running a marathon and I am heading for the finishing line. I'm going to stand up. I'm going to walk." I watch her eyes. She believes it.

After the last patient has been kissed goodbye, I ask Ogali how he learnt 'mind instruction'. "First I investigated psychics, mediums, and the telepathic world," he says, rolling a cigarette and watching his small son bicycle across the consulting room. "Then I taught myself conventional medicine. I opened myself up so I can understand it all. My questions always took me directly to where I could get the answers from. When I see my patients, I move through my mind so I understand exactly what they feel. I enter their energy and I bring myself into such focus that I feel their ailment myself. I use their instinctive memory, of walking and of health. I resolve the difficulties from the depth of the unconscious mind."

Ogali is writing a series of books on disease and remedy. His literary agency, he tells me, used to represent Sigmund Freud. Ogali insists that his methods can be taught and, if his principles are eventually accepted by the medical establishment and the government, a small army of mind instructors will march out from his mews.

For now, this is unlikely. Ogali's campaign for recognition by the NHS has failed; his letters to the Department of Health are unanswered. In neurological circles, he is dismissed as a quack who prescribes nothing more powerful than counterfeit hope.

Edzard Ernst, professor of complementary medicine at the Peninsular Medical School in Exeter explains the medical establishment's mistrust of "alternative" healers and "miracle" cures. "It is impossible to make judgments with anecdotal evidence," he tells me. "Anecdotes are meaningless. It is only through proper research that our knowledge advances. Hratch Ogali should provide proper evidence with clinical trials. If he is potent then everyone should benefit from him. I am not saying he is a crook - it is possible he has a power - but if he wants recognition he shouldn't go through the media. He should go through science."

Then why, I ask Ernst, do Ogali's patients' testify to recovery? My desk is covered with letters from them, exalting his methods. "Motivational healing like Ogali's raises patient expectation," Ernst says. "Their belief in the possibility of recovery is increased by the healer's intervention and this belief can move mountains. But it is wrong," he adds, "to make patients believe that there is a supernatural power that can heal." He then explains the placebo effect. "When there is residual function," he says, "and if you are told incessantly that you will be better then you will be better. But it is unreliable and it is not unique to Ogali."

Ernst tells me the story of the Spiritual Healer experiment, which took place in Exeter five years ago. "We teamed five spiritual healers with five actors pretending to be spiritual healers," he says. "After they had learnt to be spiritual healers the actors had the same effect on the patients as the healers." He clears his throat. "If anything, they were a little better."

But Ogali's belief in his ability to heal is absolute; his patients are his evidence. "If you focus," he says, "you learn that you possess all sorts of powers that are natural. Psychic power is natural. Telepathic power is natural. We all possess this strength but the will and the concentration and the determination to overcome must be absolute." He blows cigarette smoke to the roof of his consulting room. "It is within us."