Patients who suffer from cluster headaches - a debilitating medical condition for which there is no cure - are flouting the government's ban on magic mushrooms because they say the psychedelic fungi are the only thing to relieve the pain of their attacks.
In the past two years scores of British cluster headache sufferers have turned to magic mushrooms, prompted by reports from the US that suggest that LSD and psilocybin - the active ingredient of magic mushrooms - may be able to control the intensity and duration of their headaches.
Although some have experimented with psychedelics before, the majority have no history of drug taking. But many say they would rather risk jail than forgo a substance that lets them lead a normal life.
Richard Ayliffe, 39, a chronic sufferer from Dudley in the West Midlands, says he has tried conventional treatments but the only thing to have brought him relief is magic mushrooms. Without them he says he would not be able to hold down a job.
"People are quite sympathetic at first but once you've let them down for the third time sympathy turns to exasperation," he says. "Magic mushrooms have enabled me to lead a normal life."
Like other members of ClusterBusters - an online forum where cluster headache sufferers swap notes and discuss alternative treatments - Ayliffe claims that taking magic mushrooms not only interrupts his cycle of headaches, but buys him longer remission periods between attacks. Some sufferers claim that since taking mushrooms they have been pain-free for up to two years.
And, because an attack can come at any time many members stockpiled mushrooms ahead of the government's ban this month.
Last week one member of the group, a 41-year-old father of two who asked to be identified only as Lee, admitted he had already taken one dose in contravention of the ban.
Under the Drugs Act 2005 possession of magic mushrooms is a class A offence punishable by a seven-year prison sentence. Previously, only psilocybin and other preparations of mushrooms, but not the fresh product itself, were controlled.
"The way I see it, either I break the law or forgo the most effective treatment I have found in nearly six years," says Lee.
Since he began taking mushrooms a year ago, he says the intensity of his headaches has shrunk by a third and the remissions between attacks have lengthened to 40 days.
"It's absolutely incredible," he says. "I can't tell you how much magic mushrooms have changed my life."
Spurred by the cases, researchers at Harvard Medical School are hoping for permission from the US food and drug administration to conduct a controlled trial.
John Halpern and his colleague Andrew Sewell have collected 60 case studies from members of ClusterBusters. With the support of the Boston-based Multidisciplinary Association for Psychedelic Studies (Maps), they plan to publish the cases in a leading journal with a view to getting FDA approval for a clinical trial next year.
Maps is already sponsoring an FDA trial of psilocybin for the treatment of obsessive compulsive disorder.
"At this stage we are not advocating anything - we're just trying to gather information and see if we can get a sense of the appropriate dosage," says Rick Doblin, the president of Maps. "Having said that, I find the anecdotal reports pretty convincing."
Cluster headaches come in cycles and are caused by a swelling of the blood vessels in the brain. Sufferers say the pain exceeds that of passing a kidney stone or of childbirth without anaesthetic.
Some have found the pain, which typically extends over one side of the head and face, so unbearable that they have committed suicide.
For episodic sufferers, the headaches typically last several weeks then disappear. But in chronic sufferers - of whom there are an estimated 6,000 in Britain - attacks occur daily, with no more than two weeks' remission in any 12-month period. They can continue for years.
Conventional treatments include oxygen and Imitex (sumatriptan), an anti-migraine medication that constricts the flow of blood in the brain. Since only two injections can be taken in a 24-hour period, however, this is of little use for chronic sufferers.
Verapamil, a calcium channel blocker, can also be used as a prophylactic against attacks, - but to be effective it has to be taken in high doses, increasing the risk of such side effects as cardiac arrest.
Peter Goadsby, professor of neurology at the Institute of Neurology, University College London, and the world's leading expert on cluster headaches, is sceptical about the mushroom therapy.
He argues that the relief reported by some patients may be a placebo effect or owing to natural remission. But he does believe the cases warrant a proper clinical study, particularly as ergotomine - which contains lysergic acid, a precursor of LSD - has been used to treat migraines for years.
"It's possible that mushrooms have some useful effect but it's far from proven," Dr Goadsby says. "Cluster headaches are such a devastating problem that people will turn to anything that seems to work."
But one sufferer, John Hobson, 36, from Barnsley in Yorkshire, says since experimenting with mushrooms last year his night-time attacks have ceased and he no longer gets headaches early in the morning. But because of the change in the law Mr Hobson says he has decided to discontinue the therapy.
"If I could have mushrooms growing in my garden for medical use and I knew I wasn't going to get lifted by the vice squad I would most definitely do it," he says.
"I think the government should introduce an exemption for people in need."
Tuesday 2 August 2005 01.27 BST