It was at such a club three years ago that Lawrence took the illegal drug ecstasy. What happened next is promising to turn established theories about Parkinson's disease on their head. While experts still warn strongly against Parkinson's sufferers taking ecstasy, Lawrence may have stumbled accidentally on the nearest thing yet to a reliable treatment for the disease, which afflicts an estimated 4 million people worldwide. Within half an hour of taking ecstasy, Lawrence felt more than just the sense of elation users of the drug experience. For the first time in years, he regained control of his body, and he retained it until the next morning. "It was like a Road to Damascus," he told Time. "I was suddenly looking down at my body aware that the twitching had gone, and I had this incredible fluidity. I was completely normal."

At first, Lawrence regarded the episode as a freak occurrence. The symptoms of Parkinson's are notoriously unpredictable, and it seemed like just another of the disease's erratic turns. But then he tried ecstasy again, and once more he was able for hours at a time to regain something close to the athletic grace he once possessed. Yet when he mentioned the experience to his doctors, they dismissed it as a result of the street drug's known amphetamine qualities. So Lawrence thought little more about it, other than to make the most of ecstasy's unexpected side effect the couple of times a month he went clubbing. He also kept quiet about his chance discovery, since, in Britain as in many countries, taking the drug is a criminal offense as serious as using heroin or crack cocaine.

Now, however, Lawrence's discovery is being hailed as the beginning of a medical breakthrough. After seeing footage from a forthcoming BBC television documentary, two leading Parkinson's researchers have begun full-time investigation into why ecstasy has such a dramatic effect on his condition. The documentary, to be aired this week, shows Lawrence in a gym doing forward rolls, somersaults, backflips and swallow dives despite his debilitating condition. The researchers, Professor Alan R. Crossman and Dr. Jonathan M. Brotchie of the University of Manchester, are trying to find a component of the banned substance that might be developed into a safe drug to mimic ecstasy's good effects while suppressing the bad, which include memory loss, brain cell death and depression. And they think such a safe drug could be available for testing within a year.

Parkinson's is an incurable disorder of the central nervous system usually associated with the elderly but now increasingly affecting younger people. Sufferers include Muhammad Ali, Billy Graham, Janet Reno and, according to some reports, the Pope. But research into Parkinson's remained underfunded and under-publicized until actor Michael J. Fox announced he had the disease in 1998, having developed it a decade ago at age 30.

Parkinson's is caused by a breakdown of the brain's production of the neurotransmitter dopamine, which relays the electrical impulses involved in muscular movement. The last great breakthrough in treatment was in the late 1960s, when the "miracle" drug levadopa, or L-dopa (the chemical precursor of dopamine) was discovered to "unfreeze" patients who for decades had been practically rigid, unable even to produce facial expressions. Though it remains the standard treatment for Parkinson's, there is a serious downside to L-dopa. After a couple of years, during which patients seem to be cured, they start developing the jerky, uncontrolled twitching and tremors that most people today associate with Parkinson's.

In a healthy person, natural dopamine is released in tune with the body's needs, but using L-dopa is the equivalent of running a car's turbocharger in traffic. The result for Parkinson's patients is that their condition oscillates between hyperactivity while they are on L-dopa and immobility when they are not. Pharmacologists have been searching for 30 years for a drug to combine effectively with L-dopa and mute the turbocharger effect, but none has emerged.

Ecstasy is an amphetamine-like drug that affects emotions by boosting levels of another neurotransmitter, serotonin, which is normally connected with feeling happy. Serotonin has rarely been associated with muscular movement. Confusingly for the researchers, scans of Lawrence's brain show that ecstasy has a beneficial effect on his Parkinson's even when he takes it on its own, without L-dopa.

Researchers around the world, including Crossman and Brotchie, have suspected that serotonin may have some connection with Parkinson's and have been searching for a serotonin-stimulating drug to combine with L-dopa. They have had little success, though, and the news that the missing link may be ecstasy, or at least something in it, has cheered the Manchester duo. "The reason we're excited by Tim's case is that we've spent between us the best part of 50 years trying to understand movement disorders, and the effect we see in him with MDMA [ecstasy's scientific name] is the biggest we've ever seen," says Brotchie. "Ecstasy on its own isn't going to be a useful treatment. But the potential may now be there to develop completely new drugs for Parkinson's."

Brotchie's enthusiasm is shared by Dr. Thomas N. Chase, a neurologist who heads the experimental therapeutics branch of the National Institutes of Health in Bethesda, Maryland. "We don't work with street drugs, but we are not averse to taking clues from all sources," Chase says. "Parkinson's is a condition for which there is no adequate therapy, so if this observation with ecstasy is reliable, it could lead to a line of research which could benefit many, many people with this disease. And my guess is that this observation will pay off."

It was by chance that Lawrence's case came to the notice of researchers at all. Documentary director Jemima Harrison of Carlton Television, which produced the bbc documentary, was making what looked like a routine report on Parkinson's research. A friend of hers had recommended Lawrence as an especially articulate sufferer. "We were talking about filming him trying a new surgical technique in Spain," says Harrison. "Then one day I asked him out of curiosity if cannabis helped him at all. He said no, and I nosily asked if he'd tried any other drugs. He said, 'Well, I occasionally take ecstasy, and it renders me completely normal for several hours.' So I started looking up the science, and it seemed impossible for ecstasy to have that effect. That's where it started getting interesting."

Lawrence is uneasy about his impending celebrity: the former British soldier's views on drug use are far from libertarian. "Other people take ecstasy because they want to be in an impassive state, have a different perception listening to music and to dance all night. I do it to experience normality. But I also feel the heightened sensory perception, and I wouldn't want to be experiencing that on a daily basis because you wouldn't get anything else done. So if there is an outcry over my using ecstasy, if I was investigated and if people were really anti, I'd have to be a bit more careful." Yet if the research Lawrence has inspired somehow does pay off, nobody is likely to fault him simply for wanting to dance.