Another rancorous row about the classification of illegal drugs is looming. The Advisory Council on the Misuse of Drugs met yesterday in London to discuss whether ecstasy should be downgraded from Class A to Class B. Experts will present evidence to the organisation's panel and a report will be issued next year.

The incoming head of the ACMD, Professor David Nutt, has pointed out that ecstasy is less harmful than cocaine or heroin, which would support the case for reclassification. But senior police officers have written to the council warning that ecstasy should remain a Class A drug. The Home Office has also made it clear that it sees no case for a reclassification.

It is not hard to foresee where this process is likely to end. The Government set a precedent earlier this year by ignoring the recommendation of the ACMD over the classification of cannabis and returning that drug to the Class B category. But the arguments for a different approach to dealing with ecstasy is strong.

Ecstasy is certainly not harmless, and there are clear examples where it is linked to the deaths of users. But the threat it poses to health certainly does not merit it being bracketed with heroin and crack cocaine, which kill far more. The fact is that the present rating system of harm suffers from a serious credibility problem.

For another thing, the present law is being flouted on a staggering scale. Possession of ecstasy, as a Class A narcotic, carries a maximum sentence of up to seven years and dealers can face life imprisonment. And yet it is estimated that some 250,000 people in England and Wales regularly take the drug.

There is an assumption, shared by many in the police, that downgrading a drug will encourage young people to take it, that it would send out an undesirable "message" to the public. But it need not be this way. If a reclassification is combined with public education and advertising campaigns warning of the risks of taking a narcotic, the overall message could still be negative. Social pressures can change or affect choices, as we have seen with the public smoking ban.

The reduction of social and physical harm ought to be the guiding principle towards drugs policy. This is the approach that has been recommended by, among others, the House of Commons' Select Committee on Science, the Academy of Medical Sciences and the UK Drug Policy Commission. If we want to make our drugs laws more respected and more effective, that is the road we need to go down. The reclassification of ecstasy would be a good first step on that journey.