The fungal kingdom is making a bold incursion onto British high streets where, through a curious legal twist, magic mushrooms are openly available for sale. MARK PILKINGTON reports back from a trip to the shops.

On the morning of 3 October 1799 a man known only as JS was found wandering in a state of delirium around London's Green Park, not far from what would soon be Piccadilly Circus. He complained of waves of giddiness, odd flashes of colour across his eyes and a cramped stomach. His family suffered the same effects and feared that they were dying. All that is, except their eight-year-old son, Edward, who seemed to find their situation hysterically funny.

A passing doctor, Everard Brande, was summoned to the scene, where JS told him that the symptoms had begun not long after the family had picked and eaten their usual breakfast of wild mushrooms. Intrigued by this puzzling scenario, Brande would write in The Medical and Physical Journal that the family's condition was caused by the "deleterious effects of a very common species of agaric (i.e. mushroom), not hitherto suspected to be poisonous."

Family S hold a unique position in history, as the United Kingdom's first recorded shroomers.

England's most common indigenous psychoactive mushroom is the Psilocybe semilanceata, known to its friends as the Liberty Cap. Four to eight centimetres tall, nipple-headed and a rich cream colour, following the Autumn rains of September and October they dot our green and pleasant land in their millions. Individually they won't do anything for you - though veteran shroomers may eat one or two as they pick in a fresh field, claiming that it helps them to spot other mushrooms - but in doses of twenty or more, eaten as is, or brewed in boiling water, the effects can be potent. In fact, they're more or less indistinguishable from the effects of the 120 or so other psilocybian mushrooms found the world over - including the cubensis and mexicana, which are no doubt familiar to many Arthur readers.

The sight of plastic bag carrying longhairs bent double, scutinising our autumnal pastures for a taste of freedom has been a common one for the past three decades or so. But recently the fungal landscape has taken a dramatic and surprising turn.

About two miles North from where Family JS took their historic trip into the fungal kingdom is Camden Town, a legendary pilgrimage site for punks and Goths the world over. Here the once-thriving Counterculture of independent book and record shops has been firmly superceded by the ever-familiar counter culture of Gap and co. Shifty-eyed, muttering passers-by offer you all manner of illegal substances, but we'll ignore them and head for one of the many stalls offering an altogether more rewarding - and currently legal - psychoactive experience: magic mushrooms.

Conspicuously moist in unmarked plastic tubs are a range of mycological exotica that would, as little as three years ago, have seemed inaccessible to all but the most adventurous ethnobotanist. Psilocybe cubensis strains from Mexico, Columbia, Peru, Ecuador and Thailand sit alongside the connoisseur's choice, Hawaiian Copelandia cyanescens and what's known as Philosopher's Stone, "truffles" or sclerotica - underground growths - of the Psilocybe tampanensis or mexicana. Prices are typically £10 ($18) for 10g, depending on what and where you buy. Some stalls now also sell mescaline-containing cacti like San Pedro and Peyote, though these are slower to grow and so more expensive.

The mushrooms' packaging tends to contain little or no information: the more organised suppliers will include a label identifying the country of origin, alongside a variety of legal warnings, but you won't find any dosage or storage recommendations and no tripping tips. Only qualified herbalists can legally distribute such information, though most stallholders will answer specific questions and the better stalls display generalised notes about each strain of shroom. However, depending on the psychedelic scruples of a particular stall's owner, the person selling you your magic kingdom pass may or may not know anything about what it is they are selling.

As well as key locations in London - Camden High St, Portobello Rd & Covent Garden being your best bets - the mushrooms' glittering domain now stretches to an estimated 300 vendors in towns and cities all around the country. Enterprising sorts are also offering online and telephone deliveries to your front door. But for how long?

The legal situation regarding magic mushroom sales is a precarious one. According to the UK's 1971 Misuse of Drugs Act, the active ingredients of the mushrooms, psilocybin and psilocin, are classified Class A. This places them alongside heroin, cocaine, ecstasy, LSD and LSD and speed (if it's prepared for injection). The maximum sentence for possession is seven years in prison or, for intent to supply, life. This strikingly neo-gnostic approach to drug law is shared by the United States and much of Europe: it's the mushroom's soul that concerns the authorities, not its body.

But, because they grow more or less anywhere that sheep and cows shit, including on land owned by the military and the royal family, liberty caps and the other psychoactive mushrooms that grow here - such as the Amanita muscaria, or Fly Agaric - are only considered illegal if they have been prepared. And it's this word that has proved to be the semantic loophole through which the fungi have taken to the streets.

In its recent paper The Magic Roundabout: How to deal with magic mushrooms, the UK's Transform Drug Policy Foundation (TDPF) points out that what constitutes "preparation" remains about as clear as a cup of mushroom soup. Whether freezing, refrigerating, drying or packaging psilocybin containing mushrooms will earn you a jail sentence seems to be entirely arbitrary, largely dependent on the police force and judiciary who arrest you and consider your case. Past defendants have escaped prosecution - and even had their mushrooms returned by the police - by proving that they had dried naturally in sunlight. Others who kept shrooms in their freezers went to jail.

A 2003 governmental edict did little to clarify the situation: "it is not illegal to sell or give away a freshly picked mushroom provided that it has not been prepared in any way'. To confuse matters further, in July 2004 Customs and Excise confirmed that magic mushrooms were taxable on the grounds that they were a drug (which gets hit with 17.5% VAT) rather than a food (which is not taxable). The result is a psychedelic grey area that allows street sales of psychedelic substances, but makes promoting them as such, or even providing information about them, a potential prison offence. Most suppliers, such as Psyche Deli, based in NE London, and the Shroomshop growers' collective, provide them for "ornamental" and "research purposes" only. But, without proper information, it's very difficult for "researchers", especially first time experimenters, to explore them effectively. And, because the fungi can only be sold when still full of water, even seasoned trippers can have problems getting their dosage right.

An altogether better situation would be a step beyond that which exists in Holland, where many of the mushrooms sold over here are grown. Known locally as "paddos", they can be farmed and sold legally, and are monitored by the Dutch food inspection agency, which treats them as they would any other edible produce. But once again, the law remains fuzzy, as paddos cannot be sold with the knowledge that they will be ingested. To twist things further, the Dutch Ministry of Health has produced a special information leaflet on the effects of psilocybin that is included with every mushroom purchase. Presumably this is in case the buyer should happen to trip over and accidentally swallow some of their purchase before putting it onto the mantelpiece to display to their friends.

It's also worth quoting part of the Dutch Health Ministry's official report into the effects of psilocybin: "the risks of psilocybian mushrooms are low. Acute reactions are no more severe than having a scary experience. No chronic toxicity was found. And no signs of physical or mental addiction was found."

Here in the UK it seems that the government would rather not have to confront the shroom issue head on, and is waiting either for the tabloid angry brigade, or the courts, to force a decision upon them. Unfortunately, this head-in-the-dung-heap approach is likely to result in change only when someone gets hurt or goes to jail. They seem keen not to have to force the issue: one or two shroom shops have been closed by regional councils but, despite grumblings from the Conservative party and some of the more reactionary media outlets, the current government seems extremely reluctant to get involved. Test cases in the city of Birmingham, and in Scotland, have recently been dropped by their respective courts.

The bottom line is that proper regulation and licensing of magic mushroom sellers would benefit suppliers, consumers and the authorities. Dosage and experiential information ought to be included as part of the product packaging, along with a Best Before date, so that buyers can know whether the mushrooms are in a fit state for consumption in the first place. Trippers would then know (as well as any psychedelic experience can be anticipated) what they were getting themselves into, making the experience safer and more rewarding for everybody involved. Until this happens, ignorance is unlikely to be bliss.

Meanwhile, the fungal invasion of human consciousness continues apace. It's difficult to assuage what kind of impact the availability of mushrooms on the high street is having in the wider world. Veteran psychedelic voyagers have always tended to pick Liberty Caps in copious amounts each season, often providing themselves with supplies for a whole year; so the idea of spending ten or twenty pounds on a trip seems excessive to many. How people feel about the commodification of what is, for many, akin to a sacrament, is another issue that will be worth examining if the current situation persists. Then again, some of the shrooms for sale are enticingly exotic, and you never know when you might get caught short…

Whether we're going to see a full-on rebirth of psychedelic culture of the like not seen since the UK's "Aceeeiiiid!" and Ozric Tentacles (dog forbid!) daze of the late 1980s is too early to say. The rise of ecstasy and ketamine as club drugs of choice since the 1990s has meant that synthetic psychedelics like LSD and 2CB are frustratingly difficult to come by, so, although expensive, mushrooms might just bound in to fill that kaleidoscopic void.

Recent generations of teens have grown up with E'd-up love, ketamine mong and doped-up bong as their inner-escape routes. Perhaps the uncompromising blandness of recent "alternative" teen-orientated music and culture may drive a few of the more adventurous souls to look for some new kind of kick. Or it may have already begun: at 2004's Glastonbury festival, the music weekly NME promoted the use of mushrooms by its predominantly teenaged readers, declaring " a new summer of love". Their readers' survey suggested that 13,500 festival goers - out of about 150,000 - actually chowed down, a not unencouraging estimate.

Whether todays' teens will take up the charge into the psychedelic rabbit hole with as much enthusiasm as their forebears remains to be seen. But, while the windows of organic opportunity are still open, they may not have to look much further than their local high street.