Back when he first became prime minister (how he must miss those days!), Gordon Brown was keen to show off his social authoritarianism. Perhaps he wanted to create a contrast with David Cameron's 'liberal conservatism' and win over the right-wing press. Brown's 'son of the manse' streak manifested itself in his decision to veto the Manchester super casino and slam the emergency brake on liberalizing gambling, and to announce a review of the reclassification of cannabis from class B to class C.

Well, the review is over and it appears that the Advisory Council on the Misuse of Drugs has recommended – quite sensibly – that cannabis remain a class C drug. But it also appears that – rather less sensibly – the prime minister is going to ignore their advice and have it reclassified anyway. As he eloquently told GMTV, "I have always been worried about cannabis, with this new skunk, this more lethal part of cannabis."

Let's be clear about what this means.  Possession of a class B drug carries a penalty of up to five years in prison and/or an unlimited fine. Supplying a class B drug (which could just mean giving some to a friend) carries a maximum 14-year sentence and/or an unlimited fine. Such punishments are plainly completely disproportionate to cannabis – a widely used recreational drug that is by no definition of the word 'lethal', as the prime minister claims to believe.

That's not to deny that cannabis can be detrimental to a person's mental health. But reclassifying it to class B and turning thousands of otherwise law-abiding individuals into serious criminals is hardly a sensible response. It exposes the absurdity of the government's whole approach to drugs. It also makes educating the young about drugs even more difficult: they know that cannabis is not a 'lethal' drug and when the government claims it is, they are less likely to believe anything else they say.