The Adam Smith Institute today urges the next government to rethink policy from first principles. Its book, Zero Base Policy, will nowhere be more controversial than on narcotics. It suggests that Britain's drug policy is "one of the most spectacular failures in history. Dozens of initiatives spread over many decades have left Britain with more addiction, more drug use, more drug-related crime, and more drug-induced health problems."

Dealing with drugs costs money. The Department of Health and the Strategy Unit put the costs of drug use at £15bn-£20bn per year. Although ministers and police officers have uttered tough phrases such as "zero tolerance", drug crime has steadily increased, not diminished. When a policy achieves the opposite of what was intended, rarely is more of it needed.

The ASI urges a different approach, recognising that addicts need medical help, not punishment. Many who could be helped medically avoid seeking it because drug-taking is illegal. When drugs were decriminalised in Portugal, drug addicts chose to undertake treatment.

Drug addiction should be viewed as a medical problem. Doctors and nurses, rather than police, should handle it. There should be high-street clinics, staffed by medical personnel, where addicts can receive supplies to be consumed on the premises. Subject to medical examination and counselling, they should receive a free supply to use within the building. The medical examination required as a condition of supply would enable monitoring of their health, and counselling could help dependent users to better control the adverse physical effects of drug use.

Such a policy would eliminate the crime associated with hard drugs such as heroin. Users who currently fund their habit by criminal behaviour would not need to, since the supply would be free, costing the state very little.

This would work for some narcotics, but not recreational drugs. Addicts might take their fix of heroin in a clinic, but not social users of recreational drugs. Few people would want to enter a high-street clinic to take an ecstasy tablet – this is something used in clubs. Similarly, few people would want to snort a line of cocaine in clinical and antiseptic conditions. Neither would people want to smoke cannabis in a clinic. They would shun the medical conditions envisaged for supervised use. The cafes in the Netherlands in which cannabis use is tolerated are rather more social and relaxed than medical clinics.

The policy that could succeed would be to medicalise hard drugs, and to legalise the production and sale of recreational drugs such as ecstasy, cocaine and cannabis. They would no more be without controls than alcohol and tobacco are without controls, but no longer criminal.

The street price would collapse without the need for illegal supply. Quality could be controlled and subject to regulation and labelling. Advice could be given on packages warning of associated dangers, and alerting users to the early signs of adverse health effects.

Would their use increase? Many people choose not to smoke, even though they could. They rate the costs and health hazards of smoking higher than any pleasure it brings, and most people are moderate drinkers, even though binge drinking is legal. The same could be true of drugs.

Drugs are currently out of control and widely available. Without illegality, the criminal culture they sustain would disappear, creating a far preferable situation.