Analysis: Will Cameron be the prime minister who admits the war on drugs has failed?

Something interesting happened ahead of today's home affairs committee report into drug law. As the report sat in journalists' inboxes, the Daily Mail got a call from an unnamed source on the committee who told them it would recommend the establishment of a royal commission into current policy. MPs were 'paving the way' for drug legalisation, the paper said.

Committee chairman Keith Vaz hit out on Twitter. "Mail on Sunday article on HASC Drugs report with bizarre front page inaccurate and wrong," he wrote on Sunday morning. "Full report published tonight at Midnight." Vaz was completely overplaying the point. While it's true that the committee stops well short of recommending legalisation – or even a more liberal drug policy – its sympathetic hearing to views which would have been considered blasphemous just a few years ago is revealing.

Vaz's reaction suggests he learned from the mistakes of his predecessor committee, which called for the reclassification of ecstasy ten years ago. It did so reluctantly, after hearing evidence of how criminal sanctions were disproportionate given the health risks of the drug. Then-home secretary David Blunkett was quick to rule out any change in the law. Tony Blair was far too afraid of the tabloids to dare be liberal on drugs. Even the decision to downgrade cannabis was reversed once Gordon Brown got into power, as a way of cementing his friendship with Mail editor Paul Dacre.

Today, Vaz and his fellow MPs made every effort to learn from those mistakes. They edge the cause of drug liberalisation along without rocking the boat too much. The central recommendation of their report is that Cameron set up a royal commission "to consider the best ways of reducing the harm caused by drugs in an increasingly globalised world". If Cameron was ever to adopt a more liberal policy he would have the shield of this weighty commission, whose clout makes it difficult for prime ministers to avoid their recommendations. Furthermore, it would only report in 2015, three years from now.

The most telling phrase in the committee's proposal is: "increasingly globalised world". While the report does not go so far as to recommend liberalisation, it is uniquely sympathetic to those who do. The committee's visit to Bogota, to visit Colombian president Juan Miguel Santos, sees MPs report back that "the possibility of a different approach to the war on drugs had to be considered".

It goes on: "The president stressed throughout our discussion that he was not advocating the legalisation of drugs, but the establishment of a new international consensus around the best way to tackle the problem. He was, however, keen to emphasise that legalisation should not automatically be ruled out as a possible part of a global solution. He pointed out that whereas in consumer countries such as the UK, the problems created by the consumption of illegal drugs  were predominantly associated with health and crime, in supplier countries such  as Colombia, they were problems of national security."

The committee's recognition of the globalised ramifications of British and US drug policy is one of the first times MPs have collectively started to highlight the various ramifications of drug laws. The committee is at its most robust when discussing the Misuse of Drugs Act 1971. "The message from Colombia and other supplier and transit states is clear—what the international community is currently doing is not working," the report says. "We are not suggesting that the UK should act unilaterally in these matters, but our government's position must be informed by a thorough understanding of the global situation and possible alternative policies. This inquiry has heard views from all sides of the argument and we believe that there is now, more than ever, a case for a fundamental review of all UK drugs policy in the international context."

MPs were clearly impressed by what they saw in Portugal, which effectively decriminalised personal possession ten years ago. "This legislation was not uncontroversial at the time, and its opponents feared that it would remove disincentives to drug use and turn Portugal into a haven for drugs tourism," the report notes. "However, during our visit we were struck by the broad consensus in support of the policy. Even MPs, including many on the right, who had originally opposed the legislation in parliament told us that their fears had not been realised. Indeed, despite asking everyone we met about their views on the policy, we did not encounter a single person who opposed it. We were impressed by what we saw of the Portuguese depenalised system. It had clearly reduced public concern about drug use in that country, and was supported by all political parties and the police. 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."

Meanwhile, the experiments in cannabis legalisation in Washington, Colorado and Uruguay provided a wealth of research opportunities. "We recommend that the government fund a detailed research project to monitor the effects of each legalisation system to measure the effectiveness of each and the overall costs and benefits of cannabis legalisation."

It is remarkable how open MPs are to policies which would have been unthinkable a few years ago. They may try to downplay the significance of the report, but it is an important sign of a change of thinking in political circles.

The momentum around the world for a new view on drugs policy has clearly had an impact on the MPs. They know Cameron can ignore a select committee but is less likely to ignore a royal commission so they have guided him in that direction to maximise the chances of a rethink. Meanwhile, Vaz smacks down anyone suggesting the committee is proposing liberalisation. They are playing a delicate game, but their sympathies are obvious.

It comes at a uniquely opportune moment. The tabloids are weak as they try to prevent the Leveson inquiry's proposal of press regulation with a legislative underpinning. Cameron has come out to fight their corner and earned some political space in the process. His own views on drugs are thought to be progressive. He sat on the home affairs committee when he first became an MP and voted in favour of recommendation 24, which demanded "the government initiates a discussion within the Commission on Narcotic Drugs of alternative ways—including the possibility of legalisation and regulation—to tackle the global drugs dilemma".

As Countess Amanda Fielding wrote on last week, politicians often lose their belief in drug liberalisation once they reach office. But Cameron has another incentive. He is in government with the Liberal Democrats, easily the party most sympathetic to drug legalisation in parliament.

The international consensus that the war on drugs is a categorical failure is unprecedented. The tabloid press is unusually weak. The top of the government is populated by sympathetic figures. And the home affairs committee has played a subtle, well-thought-through game. The conditions are ideal for a rethink on drug policy. If it doesn't happen now, it may never do.

Update: The Home Office showed little sign of giving way in a round of morning media interviews. On the Today programme, minister Jeremy Browne refused to accept the war on drugs was failing. It appears the home affairs committee report will be gathering dust.