Britain should consider legalising drug use and examine international models of decriminalisation, lawmakers said on Monday in a report likely to spark fierce debate within the coalition government.
Parliament's Home Affairs Committee said Britain's drugs policy was not working and called on Prime Minister David Cameron's Conservative-led coalition government to appoint a royal commission to review the issue.
"We believe that there is now, more than ever, a case for a fundamental review of all UK drugs policy in the international context, to establish a package of measures that will be effective in combating the harm caused by drugs, both at home and abroad," it said.
It said it had been impressed by Portugal's decriminalised regime, where users are not prosecuted over the possession of small amounts of drugs and are instead referred to a non-criminal "dissuasion commission".
"Although it is not certain that the Portuguese experience could be replicated in the UK, given societal differences, we believe this is a model that merits significantly closer consideration," the committee said.
The government should also fund research into the effectiveness of marijuana legalisation in the U.S. states of Washington and Colorado, as well as into Uruguay's proposed state monopoly of cannabis production and sale, it said.
Drug dealers continued to thrive while far too many users were not in treatment or failed to shake off their addiction, it said.
The committee can only make recommendations and has no power over the government, but its reports can influence policy.
Illegal drug use in Britain is falling and is almost at its lowest level since measurements began in 1996, but more than 300,000 Britons are estimated to be addicted to heroin or crack cocaine.
Drug policy is a highly politicised issue in Britain, where alcohol and tobacco are legal but recreational drugs are prohibited.
Ministers in 2009 reversed a move to lower the criminal penalties associated with cannabis and sacked the head of the government's drugs advisory body after he said marijuana was less harmful than alcohol.