The Skunk phenomenon (2/4)

The fact that hemp is cultivated in other EEC countries means it is legal for someone to sell hemp seed in Britain, as long they are not "knowingly" selling seeds that are going to be used to grow cannabis. In the last few years, grow shops supplying horticultural equipment have sprung up selling hemp fish bait (hemp is a traditional angler's tool) as well as growing equipment. Ten seeds can be bought for between £40 and £70.

Most home-grown weed is grown hydroponically - in nutrient rich liquid, rather than soil. The plants start to bud when daylight is reduced to about 13 hours a day, which happens, naturally, in September. By manipulating the amount of light the plants receive, a grower can be smoking high-quality skunk after 12 weeks. You don't need to study Gardener's World to nurture a crop - the key is to simply remove all the male plants before their pollen fertilises the females and downgrades their THC-rich glands. On average, each plant yields a half to two ounces of smokeable material in every 14-week cycle. A few plants, then, can keep all but the most couch-ridden smoker in dope. In lofts, cellars and innocent looking lock-ups, on windowsills and between the marrows (purists swear by organic dope over hydroponic), they are doing just that, serving a disorganised army of stoners. Larger scale dope growing, meanwhile, in the railway arches, abandoned barns and isolated farms of Britain, has become an increasingly creative and audacious activity. In the Home Counties, smallholdings complete with animals have been found to disguise underground containers-cum-'greenhouses', powered by generators. The upturned hull of a barge, buried under a metre of soil, has been used to form an indetectable haven. The scale is often impressive too, with 8,000 skunk plants recovered from second world war army shelters in north Wales.

Rural police forces have become so alert to skunk production that many gangs are moving back into the towns and cities. In a house in Hampshire that was raided recently, every room was found to be stuffed with Northern Lights. Three years ago, right in the heart of Manchester, police broke through a wall and a steel door to uncover a complex set-up involving 1,000 plants. With skunk retailing at £20-25 an eighth, the potential profits are clear, and the increase in home-grown weed has caused the price of a kilo of hashish to fall from around £2,500 to £1,500 in the last couple of years.

But the police have a formidable armoury. Their helicopters have infra-red cameras which can pick out the heat of the lamps - notice that snow never settles on a dope grower's roof - while nosy neighbours will report funny smells. Grow shops are at risk of surveillance and having their records seized. And Boots' photo labs, for example, will report photos depicting any suspected illegal activity.