Increasingly the assertion is made that international drug control policies have failed and the best solution would be to legalise drugs so that they would be controlled and distributed safely through Government authorised outlets, thus denying the trade to criminal traffickers.

Regrettably, these assertions are often made by self-appointed groups with grand sounding titles which have their own reasons for supporting legalisation. Frequently high-profile people claim legalisation is the best way of addressing a major social problem without cogent supporting evidence. The data used and distributed is inaccurate but presented to impress people who believe it must be true because it is published by such impressive sounding organisations and respected "celebrities".

The flawed argument is that all prohibition monies have been wasted and would be better spent for the benefit of the community; it is claimed taxation on legally supplied drugs could be used to offset problems arising from drug use.

The truth is that all drugs are potentially dangerous including prescription and over-the-counter medicines unless taken under medical guidance and supervision. International organised crime has capitalised on drug trafficking to the point where the money generated often exceeds the GDP of many countries. Traffickers spread false information aimed at convincing gullible people that drugs are safe "recreational" and fun; it has to be remembered it is the demand for drugs that has made trafficking so profitable. Accurate information has been submerged by an abundance of deliberately false statements about all drug users being treated as criminals and drug control is an abuse of human rights which should allow all people freedom of choice.

Elementary research will reveal the problem with uncontrolled drugs just 100 years ago was vast and there were many people addicted to hard drugs marketed in various forms and widely used and abused. The international drug control system was born out of a real humanitarian crisis, a catastrophe that happened only because of a lack of global norms and standards. The UN Conventions were developed because it was universally agreed control was necessary to protect the health and welfare of mankind and most countries became signatories to agreements that are reviewed and approved every decade. The main Convention of 1961 is flexible in its approach and, far from being all about arrests and imprisonment, it emphasises the need that drugs should be used only for legitimate medical and research purposes; it stresses health and requires that all drug users are treated with respect and not marginalised or discriminated against. Conventions encourage evidence-based therapy for those who become dependent as well as education, rehabilitation and social re-integration. Criminality also has to be addressed.

There is another important UN Convention on the Rights of the Child, 1989, designed to protect children from the illicit use of narcotic drugs and psychotropic substances and to prevent the use of children in illicit production and trafficking. This is important as the human brain does not stop developing until well into the 20s and substances such as cannabis are proven to damage the brain permanently.

The purpose of any effective drug policy should be to lessen the harm that illegal drugs do to society. Lowering or eliminating current legal and social restrictions that limit the availability and acceptance of drug use would have the opposite effect.

Any Government policy must be motivated by the consideration that it must first do no harm. There is an obligation to protect citizens and the compassionate and sensible method must be to do everything possible to reduce dependency and misuse, not encourage or facilitate it. Criminals will not stop their crimes, change course and become honest tax-paying citizens if drugs were legalised. Although there may be freedom of choice to use dangerous substances there can be no freedom from the consequences. International drug control is working; fewer than 6% of people globally use drugs regularly and legalisation is not the answer.

Dr Oliver was a police officer for 37 years and is an independent consultant for the United Nations Office on Drugs and Crime. He is the author of Drug Affliction, published by The Robert Gordon University, Aberdeen.