Leading article: Precaution and prohibition

Public alarm over mephedrone has got out of hand. Answering a perceived new drug threat with an ill-thought out response rarely works and risks causing more harm than good. In the 1980s, attempts to restrict sales of glue to over-18s to curb an apparent epidemic only succeeded in making life difficult for young aircraft model makers.

Politicians are programmed to follow the precautionary principle – as we don't know how dangerous mephedrone is, let's ban it until it can be shown to be safe. Scientists demand evidence of harm first, before moving to prohibition, because of the danger that prohibition itself causes harm. Though the drug has been linked with 18 deaths, no post-mortem confirmation of its role, if any, in the deaths is yet available.

Criminalising users, who would then be threatened with possible imprisonment, seems premature for a drug whose harms are still unclear. Moreover, prohibition tends to push prices up and purity down, increasing health risks and encouraging acquisitive crime. It also forces production and supply of the drug underground.

If the harm caused by the drug is later found to be less than was thought, it is highly unlikely any government would take the politically difficult decision to downgrade a drug it had previously warned was dangerous.

Against that, supporters of a ban argue that the very fact that mephedrone is "legal" and not specifically outlawed under the Misuse of Drugs Act – though banned for human use (and thus sold as "plant food" or "fertiliser") – means some people are emboldened to try it who would not otherwise dabble in illegal drugs. If that is the case, there are other ways of restricting use than employing the blunt instrument of an outright ban, with the risk of collateral damage it carries.

Education about the nature and risks of mephedrone should be the first priority. A clampdown on selling drugs of any kind, legal or illegal, in or around schools should be rigorously enforced. The internet may need to be policed and websites offering the drug shut down. A response of this kind to the perceived threat would be proportionate. An outright ban would not.