Leading article: Cannabis: a retraction

Yes, our front page today is calculated to grab your attention. We do not really believe that The Independent on Sunday was wrong at the time, 10 years ago, when we called for cannabis to be decriminalised. As Rosie Boycott, who was the editor who ran the campaign, argues, the drug that she sought to decriminalise then was rather different from that which is available on the streets now.

Indeed, this newspaper's campaign was less avant-garde than it seemed. Only four years later, The Daily Telegraph went farther, calling for cannabis to be legalised for a trial period. We were leading a consensus, which even this Government - often guilty of gesture-authoritarianism - could not resist, downgrading cannabis from class B to class C.

At the same time, however, two things were happening. One was the shift towards more powerful forms of the drug, known as skunk. The other was the emerging evidence of the psychological harm caused to a minority of users, especially teenage boys and particularly associated with skunk.

We report today that the number of cannabis users on drug treatment programmes has risen 13-fold since our campaign was launched, and that nearly half of the 22,000 currently on such programmes are under the age of 18. Of course, part of the explanation for this increase is that the provision of treatment is better than it was 10 years ago. But there is no question, as Robin Murray, one of the leading experts in this field, argues on these pages, that cannabis use is associated with growing mental health problems.

Another campaign run - more recently - by this newspaper is to raise awareness of mental health issues and to press the Government to improve provision for those suffering from mental illnesses. The threat to mental health posed by cannabis has to take precedence over the liberal instinct that inspired Ms Boycott 10 years ago.

Many elements of her campaign remain valid today, however. The diversion of police resources into picking up easy convictions for cannabis possession was a waste. The rhetoric of the "war on drugs" tended to distort priorities: the current shift towards a strategy of harm reduction is a long overdue correction. Where we part company with her is on her view that the legalisation of all drugs is desirable because it would end the involvement of organised crime. So it might, but the fact that the possession of cannabis - and other drugs - is illegal acts as an important social restraint.

In fact, there is a strong case for believing that the present state of the law and of government policy is about right. The way the police enforce the law seems to be a reasonable compromise, while the emphasis of public policy is on information, education and treatment. The more the facts can be driven home about the differences between old-style hash and modern skunk, and about the risks to mental health, the better. And the more that policy towards drugs generally focuses on the causes of addictive or self-destructive behaviour, rather than locking people up, the better still.

The growing evidence of the risk of psychological harm posed by cannabis means that the time has come for us to reverse one of the positions with which - before the Iraq war - this newspaper was most identified.

We quote John Maynard Keynes in our defence: "When the facts change, I change my mind. What do you do, sir?"