A legal cannabis market should be tested and drug use decriminalised in order to try a radical new approach to drug use that focusses more on human rights laws, a group of MPs and peers has said.
The All Party Parliamentary Group for Drug Policy Reform called for an overhaul in global narcotics policy, saying the "war on drugs" and "blanket prohibition" approach had failed.
It said experiments into possible models of regulated markets for marijuana should be "encouraged" among United Nations countries including the UK. In a report, the group said:
It also said any regulation should reflect the "supremacy" of human rights conventions.
Cannabis has already been legalised in parts of the United States.
Co-chairwoman Baroness Meacher urged the ministers to test a controlled system where licensed premises sell labelled and tested cannabis which she said could undermine dealers who sell more dangerous substances.
The independent peer said: "I think it would be wonderful if our government would introduce a trial of a regulated market."
It was one of a number of conclusions in a report setting out the group's interpretation of United Nations drug conventions, which were originally drawn up in 1961.
It also said: "States parties are able to decriminalise the use of all controlled drugs, and their possession for personal use, within the Conventions." Baroness Meacher said evidence from Portugal, where drug use was decriminalised in 2001, showed that such an approach can have benefits such as reduced addiction levels.
The report said there was an immediate need to introduce an "experimental ethos" in an approach which has "less focus upon prohibition and punitive measures, and greater emphasis upon human rights, public health and social welfare".
Baroness Meacher said the current approach is "ignorant, not based on evidence and over 50 years has been shown to have failed".
Human rights laws, and in particular a provision that covers the right to respect for private and family life, could be used to claim that those who possess or buy drugs should not be treated as criminals, the study suggested.
It said: "For European countries, the European Convention on Human Rights, in particular Article 8, could be invoked in support of the argument that possession or purchase (or cultivation of drugs for personal use) (particularly in small quantities) do not injure other people's rights either directly or indirectly and therefore should not be criminalised.
"Nonetheless, harms to third parties can arise from the use of drugs (as with the use of alcohol). Such as harms to the children of drug users and harms arising from drug driving. These need to be addressed by the most effective means."
Drug control measures must conform to human rights agreements, meaning the death penalty should not apply to supply or possession offences.
Essential pain relief medicine should be accessible in each member country.
Aerial crop eradication should be stopped and replaced with carefully targeted crop interventions
A spokesperson for the government said: "This Government has no intention of decriminalising or legalising drugs."