Professor Nick Crofts of The Nossal Institute for Global Health and Melbourne University's Centre for International Mental Health is one of the world's leaders in drug policy. He is here in The Zone to help people understand why prohibition does not work, and how we might minimise harm caused by drug use. In so doing he is not here to encourage the use of illicit drugs. He is driven by harm minimisation - and human rights.

When Jeff Kennett was premier and Victoria was one of the world's heroin capitals, he commissioned Crofts to examine the relationship between various ethnic groups and the heroin market. The real aim was to look at the link between the Vietnamese community and the trade in drugs. The report was handed to the new government that replaced Kennett, and was buried, Crofts says.

''One part of the research was that we interviewed something like 50 senior police, senior magistrates, senior politicians, senior public servants. Every one of them, unanimously, said, 'You are absolutely right and we totally agree with you, we need to move away from prohibition, we need another social policy, and you will never catch me saying that in public'.'' Another world leader on drug policy reform is former Brazilian president Fernando Cardoso. In a recent opinion article in The Age, he said: ''Prohibition has failed and we must redirect our efforts to the harm caused by drugs, and to reducing consumption. The war on drugs is a lost war, and 2011 is the time to move away from a punitive approach in order to pursue a new set of policies based on public health, human rights and commonsense.''

Drugs, legal and illicit, are widely used and effectively regulated in many cases. Crofts and many researchers the world over advocate moving the regulation of currently illicit drugs from the criminal justice system to the health system.

Portugal has just done this, and here in Australia we have moved some of the way by introducing a system where people can be diverted from the justice system into the health system.

''The longer I look at drugs, the more I see people. Show me somebody who has problematic drug use and I'll show you somebody with underlying problems in their lives. That is not to say there is no place for regulation.

''We're extremely skilled at regulating a whole range of different substances, from the ones that are available off the shelf at the convenience store, through to ones that are purchasable only in certain locations by certain people, in which I would include alcohol, and then through to another form of regulation, a very common form of regulation, which is prescription.''

Croft's concern about prohibition is not only does it not work, it actually makes things worse.

''Where there is demand [for a substance], prohibition is an excellent way of creating a blackmarket and all the things that go along with it, including corruption, lack of quality control, high prices. It is not a successful public policy mechanism in decreasing harm to individuals or society. In fact, if you look at where the heroin epidemic came from in the United States, it traces back to alcohol prohibition.

''As in many of these things, the irony is that the attempt at a social policy to decrease harm has actually instigated the social policy that increased harm.''

One of the greatest harms associated with failed, misguided drug policies is the relationship between injecting drugs and the AIDS epidemic. It is something Crofts has encountered through his work all over the world. ''Criminalising opium has led to the rise of heroin. The rise in heroin has led to a rise in injecting. The rise of injecting has led to a rise in HIV. And that's a big part of my work, dealing with epidemics of HIV driven by injecting drug use, driven by criminalisation of these drugs, driven by foreign policy imperatives from, particularly, the United States.''

Crofts believes injecting drug users are among the most marginalised people in the world. The full transcript of our interview is available at theage.com.au/opinion/the-zone. In it, Crofts sets out his views in great detail.

''My issue is about people. I am a public health practitioner with an aspiration to understand human rights. And if a person's drug use is causing harm to themselves and/or to other people, then, yes, there's a problem there.

''And it behoves us to offer what assistance we can to those people. But if an individual chooses to use a drug, fully knowledgeable and in control of their faculties and all those things, I actually don't think it's our place to interfere with that … I'm not pushing, advocating, condoning anything in relation to drugs. I'm saying what we're currently doing with some drugs is creating an enormous amount of harm that is not associated with the drugs themselves, but is associated with the way we try to regulate them.''

Alcohol is a far greater danger to young people than ecstasy, evidence suggests. The people who make laws, though, like alcohol - and the taxes they place on its consumption.

Evidently, a key question is what we ought to be doing with drug policy. Crofts does not have a pat answer, because what's needed is data and experimentation.

When he was prime minister, John Howard killed a heroin prescription trial of great promise that had been scoped by Australian National University's Gabriele Bammer. After two attempts, it had cleared ministerial hurdles. But the prime minister killed it on live radio when Sydney entertainer John Laws scorned the project. Perhaps a good place to move next would be for our politicians to have the courage and decency to do the trial.

''My heart goes out to the people who have lost kids to heroin. When the heroin flood was going on in the late '90s, there was a group that used to meet up at the Brosnan Centre, parents who lost kids to heroin. I met with them and talked with them and listened to their stories …

''My compassion is 100 per cent for people in that circumstance. I also know that if heroin had been available, in a regulated environment, the chances are the majority of those kids would not have died.''

It is to these families and those who will join them if change does not come that we owe the most care and sympathy, not politicians who fail to grasp the difference between being right and being popular.