British street gangs now have possession of large quantities of herbal cannabis

British street gangs now have possession of large quantities of herbal cannabis, local police know the most likely source of the drugs is a raid on a farm. Herbal cannabis, as distinct from the resin form of the drug, is made of the flowers and stalks of mature female plants. Seizures of herbal cannabis have increased fourfold in the past decade as popularity of this variety has grown. Over the past five years at least four “gardeners” have been murdered in London as a result of raids by other gangs. Over the same period the very nature of the cannabis on the streets of the capital has changed out of all recognition. In 2005, just 15 per cent of cannabis consumed in the UK was grown here, the balance being smuggled in from abroad, particulaly Amsterdam. Today the proportion of domestically farmed product had inreased to more than 90 per cent. That figure continues to rise.

This dramatic shift is due almost entirely to the arrival in the UK of organised gangs from Vietnam, who rapidly achieved near-total domination of Britain's marijuana business. The gangs employed a high level of expertise and operated a tried and trusted business model capable of generating vast profits in a short space of time.

The know-how and methodology were imported direct from Vancouver, Canada, where, in the mid-Nineties, Vietnamese gangs took over the cannabis trade previously being run by the Hells Angels. Instead of setting up rural plantations as the biker gangs had done, the Vietnamese focused on turning networks of rented houses in busy residential areas into clandestine grow-ops.

The operations were staggered so that a new crop was ready for harvesting every few weeks. If one house in the network were to be raided, profits from the others would more than cover the loss and it was a simple matter to establish a new farm in a new home. Soon the extended criminal families involved in the trade set their sights on horizons new and identical grow-ops appeared in Australia, Sweden and the UK.

By 2005 the factories were everywhere. In September that year police in Newham shut down 14 of them on a single day and judges at courts south of the river began to complain that they were struggling to tell cases apart as there were so many to deal with.

The gangs began to move out of the capital into suburban areas where police were less familiar with the warning signs, but in recent years they have focused on areas with large numbers of rental properties and transient populations where neighbours are less likely to take an interest in what is going on around them. Those living nearby are stunned when they find out what has gone on under their noses. In 2007, the Met shut 378 factories. Two years later that figure had climbed to 692. Since last April, the Met has already shut down 253 factories.

Many of these latest finds are being run by British gangs, eager to cash in on the seemingly insatiable demand for the crop. In February this year police seized a parcel addressed to a flat in Wanstead which had been found to contain thousands of pounds worth of cocaine. When the property was raided, police found it had been turned into a cannabis factory, with 22-year-old Jerome Smith hiding in the loft space.

Similarly, 45-year-old Thomas Thomas, currently serving 16 years for his part in the £40 million Graff jewellery robbery, had converted his own home into a cannabis factory. Police found dozens of cannabis plants growing under heat lamps in an upstairs bedroom of the three-bedroom house.

Like the Coes, many gangs are setting up in industrial buildings and scaling back some of their domestic operations in order to help them go unnoticed. In the past gangs would try to use every inch of space in a rented house for cultivation, but not now. “They're getting cleverer,” says Lam — not her real name — who works as a translator and has assisted in dozens of court cases involving gangs. “They won't put any plants in the living room, they'll leave the curtains slightly open and have a television on inside. One even had a Christmas tree. It's all about giving out the impression that this is just a normal family home, that nothing untoward is going on inside.”

With landlords wary of Vietnamese clients inquiring about large, isolated properties, many gangs welcome the involvement of British criminals in order to help them obtain suitable premises. Cases involving multiple nationalities are already appearing in courts and police expect this trend to continue. It also seems certain that the violence associated with the trade is set to grow.