Price and availability of a given drug are generally taken as the key markers of success or otherwise of the "war on drugs" campaign, and the figures for marijuana do not suggest that this is money well spent; in relative terms the first has come down and the second gone up.
The illegality of cannabis forms part of the windfall to organised crime that prohibition provides, criminalises a section of the population many of whom would not otherwise dream of committing any offence, and necessitates contact with the "underworld" to obtain supplies.
Alcohol and tobacco are arguably more toxic and addictive than cannabis, and the intoxication associated with alcohol can be much more dangerous and disruptive to society.
Internal restraints reinforced by family, peers and cultural pressures - which restrain alcohol use effectively in most of the population despite widespread availability and promotion - are far more powerful than external, legal restraints.
Growing cannabis in the greenhouse is a classic victimless crime; it may prove damaging to the individual, but eggs and cream are not controlled just because over-indulgence may induce heart attacks.
Cannabis has been used as a medicine in China, India, the Middle East, southern Africa and South America for centuries. Accounts by the sages Pliny and Galen have been familiar to European doctors for more than 1,600 years. In the 19th century it was respectable enough to be used by Queen Victoria's doctor to alleviate her labour pains.
Today its classification within Schedule 1 of the Misuse of Drugs Regulations (1985) denies British doctors the right to prescribe it under any circumstances, and effectively rules out prospective research on human volunteers or patients, which might clarify its properties, both beneficial and adverse.
Today in Britain it is easily the most prevalent illicit drug; more than a third of A-level students and more than 50 per cent of Oxford University undergraduates say they have sampled it. Despite the "war on drugs", cannabis is cheap and easily available in most British schools. If the experience of alcohol is indicative the increased availability of cannabis would be associated with wider usage, although this may have more to do with commercial promotion than simply ease of access. However, a survey of Oxford undergraduates in 1994 suggested that few of those who had not yet experimented with cannabis would be tempted to do so if it were decriminalised.
The Dutch introduced de facto decriminalisation 25 years ago, but do not appear to have studied the sociological and medical impact of this in any formal way.
If cannabis use among young people did increase as a result of decriminalisation, would this replace other forms of intoxication, or add to them? Would the removal of its illicit status reduce its appeal to some people and lead to an increase in consumption of other drugs?
Given the existing prevalence of cannabis use, the complete absence of coordinated and controlled human research into the possible beneficial and adverse effects sems indefensible. Many doctors even believe that cannabis and its derivatives should be available once again on prescription.
Perhaps it is time now for the Government to truly open the debate on cannabis and review its place in the Misuse of Drugs Regulations at the earliest opportunity.Reuse content