The United Nations drug control agency has condemned a string of countries for relaxing their laws on the use of illegal drugs.
Cannabis is to be downgraded in the UK
The UN's International Narcotics Control Board (INCB), which monitors compliance with international treaties banning illegal narcotics, said such countries were undermining the fight against global drug trafficking.
Australia came under fire over its "injection rooms" for heroin users, while several western European countries, including Britain and Switzerland, were attacked for adopting or moving towards less stringent laws on the use of cannabis.
Many of those listed have introduced laxer controls in order to focus their efforts on tackling harder drugs, or have provided monitoring rooms to try to prevent overdoses and the use of dirty needles.
But INCB president Philip Emafo said these countries were misguided.
"The truth is that there are no safe ways to abuse drugs," he declared. "Governments should not be intimidated by a vocal minority that wants to legalise illicit drug use."
Britain, which is reclassifying cannabis to make discreet possession a non-arrestable offence, has already hit back at the UN's charges.
"Reclassification of cannabis enables us to put out a more credible - and therefore effective - message about the harmfulness of different drugs," the Home Office said in a statement.
The move "allows the police to focus its resources on tackling the drugs that cause the most harm and this is a view shared by communities up and down the country."
Reclassification of cannabis enables us to put out a more credible - and therefore effective - message about the harmfulness of different drugs
International opinion on the harmfulness of cannabis remains sharply divided.
Supporters of the drug say it has wide-ranging benefits - noting in particular its positive effects in those suffering from cancer or multiple-sclerosis - but its opponents say these are cancelled out by other damage it inflicts.
There are also fears that the drug is a "gateway" to experimentation with harder substances, although recent research from the US suggests there is no such link.
A senior member of the UN Narcotics Control Board, Professor Hamid Ghodse, said at a press conference in London that Britain's policy could contribute to cannabis use being as widespread as tobacco.
This could lead, he said, to the UK's psychiatric hospitals filling up with people who have problems with cannabis.
Professor Ghodse also criticised the Australian injection rooms, saying it amounted to the authorities "giving up" in their fight against drugs.
The annual UN report says that contrary to popular myth, illegal drug production does not benefit producer countries but prevents economic growth by encouraging corruption and crowding out legitimate investment.
The report says 99% of the profits from growing cannabis and cocaine are made outside the developing countries where the crops are cultivated.