The south London borough of Lambeth has become the nation's guinea pig in the debate over whether a zero-tolerance or a softer approach works best in dealing with the cannabis issue.
In 2001 Brian Paddick, who was the local police commander, introduced an experiment in which anyone carrying a small quantity of the drug was given a warning rather than arrested and prosecuted. Those caught with the drug had their supply seized and officers were urged to use their discretion when arresting people.
The scheme caused huge controversy, but its arguable success played a part in the downgrading of cannabis.
Two evaluations of the project showed that, in the first six months, it saved 1,350 hours of police time.
Supporters said that it allowed police to concentrate on more serious drugs such as heroin and to target large-scale dealing.
However, critics pointed out that during the same period there was a 35 per cent increase in the number of people found in possession of the drug and an 11 per cent rise in trafficking offences.
The rise was blamed on the huge influx of so-called "drug tourists" into Lambeth who were lured in the mistaken belief that cannabis was legal in the area.
During the first six months, almost half of the people who received a warning after being found with the drug were from outside the borough.
Local residents complained of a rise in dealing of the drug and of people openly smoking it, particularly in the streets around Brixton.
The experiment lasted until July 2002 before cannabis was reclassified in 2004.
Even Mr Paddick believes that downgrading the drug is a step too far, saying only this week that he believed it was "unnecessary".
He still insists that his softer approach is the best way forward.
Now Lambeth is at the centre of a new experiment, where people caught with even a small amount of cannabis in certain streets will face arrest. The "No Deal" initiative that came into force in December is aimed at hitting both the supply and demand of the drug. Police have new powers to stop and search suspected dealers and buyers and anyone arrested more than once could be charged or issued with an anti-social behaviour order.
Borough police commander Chief Superintendent Martin Bridger said: "We want people to enjoy coming to Brixton without having to face drug dealing, its associated crime and the behaviour it can lead to."
Local police also hope that the three-month trial scheme will stop the " drug tourism".
For and against
DOES IT HAVE MEDICINAL EFFECTS?
Cannabis - the "aspirin" of the 21st century - may protect against ageing. Sativex, cannabis-derived, is licensed in Canada for multiple sclerosis.
Trials of Sativex in the UK have proved inconclusive. It was refused a licence in 2004 until more convincing evidence was found.
DOES IT DAMAGE THE MIND IN THE LONG RUN?
Cannabis is associated with a higher risk of schizophrenia and depression. Up to 80 per cent of new cases of psychosis are set off by cannabis abuse.
Research argues that cannabis is associated with psychosis but not that it causes it. Some 90 per cent of users are unharmed.
DOES IT HAVE HARMFUL SHORT-TERM EFFECTS?
The drug distorts perception, affects short-term memory, in heavy doses causes hallucinations and increases the risk of car and other accidents.
Nearly half of those aged 16 to24 have used it, most without ill effects. In moderation, it is relaxing.
DOES IT DAMAGE HEALTH?
Up to 30,000 deaths a year could be caused by cannabis if its damaging effects are comparable to those of tobacco, the BMJ reported in 2003.
Two long-term studies of cannabis involving more than 100,000 people in Sweden and the US found no increase in deaths.
DOES IT LEAD USERS ON TO HARDER DRUGS?
One study showed that children who smoke it are up to five times more likely to move to harder drugs than those who delay experimenting.
Another study concluded that teenagers who took hard drugs did so whether they had first tried cannabis or not.Reuse content