Progress towards a sensible drugs policy is glacially slow, but the latest report from the Home Affairs Select Committee on Britain's ineffectual prohibition laws suggests the balance of opinion at Westminster may be tilting towards common sense at last. Sad to say, the Government shows few signs of following suit.

Not only is there much to be welcomed in the committee's conclusions – there is also much that would have been unthinkable just a few years ago. MPs praise measures in place in Portugal (under which possession of small amounts of a controlled substance results in either a fine or a rehabilitation programme, but no criminal procedure); they evince keen interest in the legalisation of marijuana in two US states and also in Uruguay (where the government is proposing a state monopoly of production and supply); and they call for a Royal Commission to conduct a "fundamental review" of UK drugs policy, to report by 2015.

Quite right. Britain's existing laws are indeed, as committee chairman Keith Vaz puts it, "not working". It may be that drug use has dipped slightly in recent years. But one in five secondary school children still admits to having experimented with illegal substances at some point. And there are any number of factors outside of government policy that explain a drop in usage – the economic climate and the proliferation of "legal highs", to name but two – none of which constitutes a long-term solution.

This – liberal – newspaper would go further than Mr Vaz et al and advocate the swift decriminalisation of all drugs. First, there is a simple principle: individuals should be free to make their own choices, providing they do no harm to others. But for those not convinced by John Stuart Mill, the practicalities alone surely clinch the argument.

As Prohibition in the US proved, bans are as counter-productive as they are futile. Drugs are no different. The deterrent effect of punitive laws is minimal. Illicit substances are still widely available, and they are less pure and more dangerous; meanwhile, swathes of the population are criminalised unnecessarily, those who need help struggle to find it, and those caught out are sent to jails also awash with drugs.

Even the advent of super-strength cannabis – the dangers of which have been covered in detail in The Independent – argues for better healthcare rather than impotent sanctions that merely drive its use underground.

And all this before the rise of drugs-funded global gangsterism is even considered. With 60,000 dead in Mexican turf wars alone, and the lucrative proceeds of illegality bankrolling everything from gun-running to human trafficking to war, the sooner so pernicious a symbiosis is broken up the better.

A Royal Commission to consider UK laws is just the first, small step towards a rational, rather than moral, response to drugs. The Government has dismissed it out of hand, however, amid rather confusing Home Office claims to be "open to new ways of thinking". Changing tack on so emotive an issue is, of course, tricky for any government. But that is no excuse for this one so mindlessly to dig in its heels.

There is, then, still a long way to go. But the fact that a cross-party group of MPs is taking so open-minded a stance is, by itself, a shift that cannot be dismissed. Even less so as it comes just months after the UK Drugs Policy Commission – made up of relevant experts, scientists and police officers – concluded its six-year inquiry in favour of decriminalisation.