Drug users should be treated with compassion rather than criminalised, Sir Richard Branson has said, as he called for a rethink of current "repressive" policies on drugs.
The billionaire Virgin chief said the "war on drugs" had poured resources into jailing people and policing at the expense of education, vocational training and the treatment and rehabilitation of drug users.
"There has been now four decades of the so-called 'war on drugs' and this has done, I think, terrible things to societies everywhere. It has done damage to drug users, it has done damage to their families, it has done damage to their communities," he told the International Aids Conference in Melbourne, Australia.
"I believe it is time to support an alternative approach to the prohibitionist framework that has been in effect and has been so ineffective for decades now.
"People who use drugs or have a drug problem should be treated with compassion rather than being criminalised."
Sir Richard, a member of the Global Commission on Drug Policy, said between £1.5 billion and £2.5 billion a year in the UK is spent on the enforcement of both drug supply and possession offences.
He said the commission had long supported "non-criminal sanctions" for drug possession and for countries to consider regulating drugs to take the market out of the control of criminals.
He said countries such as Portugal, Switzerland and the Czech Republic as well as some states of Australia have all implemented schemes which divert people away from the criminal justice system for possession of drugs.
Drug use has not increased where these schemes operate, he said, and people who are not criminalised fare better in terms of employment, housing and relationships.
He added that they are also much less likely to come into contact with the criminal justice system, thereby "closing the revolving door of recidivism" .
"The UK has one of the highest GDP spends in Europe on drug law enforcement, yet it has among the highest rates of drug use in western Europe. Looking at this as a businessman, I would say that has been a pretty bad investment. It is time to to try a new model," he said.
Sir Richard said world leaders would meet in 2016 for a global summit on drugs at the United Nations.
"We need our politicians to be brave and we need them to look at alternatives to the current repressive policies," he said.