The drugs industry is a multi-billion dollar one, driven by violent criminal gangs which has killed hundreds of thousands of people around the world, but is the so-called war on drugs working?
Former UN Secretary-General Kofi Annan and former Brazilian President Fernando Henrique Cardoso, are the two world leaders who argue that repressive approaches to containing drugs have failed.
Criminalisation is creating a vast black market where it should not exist. When we're talking about things like cannabis, cocaine, heroin, these are minimally processed agricultural commodities. that are very simple to produce and cost in real terms pennies per dose, and yet because we have policies of prohibition and high demand around the world we create an astronomical price support for drug traffickers .... This is a self-inflicted wound that we have imposed upon ourselves.
Both men are members of the Global Commission on Drug Policy - and they are calling for a new approach.
In a newspaper opinion piece they wrote: "'We called on governments to adopt more humane and effective ways of controlling and regulating drugs. We recommended that the criminalisation of drug use should be replaced by a public health approach.
"We also appealed for countries to carefully test models of legal regulation as a means to undermine the power of organised crime, which thrives on illicit drug trafficking."
Those in favour of reform see the war on drugs as a colossal waste of government resources. They argue regulation could instead yield billions in tax revenues; it would be a blow to organised crime and put drug dealers out of business; and it would cut street crime and violence related to drug trafficking.
Meanwhile, those against legalising drugs say it would create a huge black market, leading to yet more addicts and more crime. They also say that an increase in the use of soft drugs could see users graduate to harder drugs, and drugs could fall more easily into the hands of children.
Drugs became a symbol of youthful rebellion and social upheaval in the 1960s, and in the summer of 1971 US President Richard Nixon first declared the so-called 'war on drugs'.
It is estimated to have cost more than $1 trillion in the four decades since then, with the bill now running at $100bn a year.
The UN estimates the drug market itself to be worth $1.3 trillion and growing, and generating profits of around $435bn a year.
Latest UN figures show some 230 million people took illicit drugs in 2011, with estimates suggesting the number of drug-related deaths could be as high as a quarter of a million.
Calls for the decriminalisation of drugs are growing stronger around the world.
Portugal is seen as a pioneer as it decriminalised drug use twelve years ago, putting possession of a small amount of drugs on a par with illegal parking.
In the US, Colorado and Washington have legalised the recreational use of cannabis for those over 21.
Chile, Ecuador and Colombia have ruled that the possession of drugs for personal use is no longer a crime. And Uruguay is considering a passing legislation which would see the government growing and selling marijuana, for as little as a dollar a gram.
So, is it time for a fresh approach to the war on drugs based around legalisation and regulation? And can decriminalisation help reduce drug abuse and organised crime?
To discuss this, Inside Story, with presenter Hazem Sika, is joined by guests: Sanho Tree, director of the Drug Policy Project which works to end the domestic and international war on drugs; Amanda Fielding, a drug policy reformer and founder of the Beckley Foundation; and Manuel Pinto Coelho, president of the Association for a Drug Free Portugal.
"It's completely wrong to spend the vast majority of the money being spent by the tax payer around the world on catching people and incarcerating them, it's just not the right approach, we should be spending it on the protection of health and security and education."
Amanda Fielding, Beckley Foundation.