Amy Jenkins: Too posh to puff? You've got to be kidding, man

There was a time, not so long ago, when the substances you chose to inhale or ingest were your own business. That was at the beginning of the last century. Then the First World War came along and fear and xenophobia came with it. Drugs such as cocaine and opium became associated with a particular class of people: "exotic" foreigners and "loose" young women. The establishment quickly saw to it that this sort of hedonism became a criminal activity. As Marek Kohn pointed out in his groundbreaking drug history Dope Girls, drug laws have always been about social control: for "crack fear" read "black fear". So it's not surprising that, at the beginning of a new century, cannabis is being downgraded to class C. Apart from a few Rastas in Brixton, "draw" must nowadays be the most middle-class drug of them all.

My own drugs education began at Pimlico Comprehensive. There the odd line of speed was popular - and some terrible stuff called amyl nitrate, which was sniffed out of a small brown bottle and made you feel like your head was going to blow off for a second or two. Oh, and something we bought in DIY shops, paint stripper or thinner or some such, which we pretended to inhale if we dared.

It wasn't until I went to private and exclusive Westminster (girls allowed in the sixth form) that I got a comprehensive introduction to stoner society. Those effete, edgy, posh boys, with their angelic faces and their skinny, scruffy, drainpiped school trousers, they're the ones I associate with "spliff". It was a religion.

Now the trousers are wider, but the religion is the same: the crispy Rizla ritual, the rolling and licking and sticking, the gasping and passing and laughing, and that little cardboard roach that comes out and sticks to your tongue.

Organically grown, or near enough, cannabis has long been thought of as the "health food" drug. The safe, tasteful, "natural" drug for those in society who think it's a good thing to eat their greens. When I was a child, it was drummed into me to never, never, never do heroin - an evil drug. And I never did. But, one way or another, I did just about everything else. Oddly, I had my most scary experiences on dope; the only really bad trip I ever had was the result of eating a hash cookie. The effect lasted a day and a half, and at its worst I couldn't look my friends in the face. They seemed like monsters to me.

The trouble with cannabis is that it's notoriously difficult to know exactly what strength of THC (tetrahydrocannabinol - the active ingredient) you're exposing yourself to. Jamaican skunk, for example, is famous for making the tourists fall over after one puff. Personally, I found the notion that cannabis is inherently mild misleading. On a good day it had me giggling like crazy; on a bad day it was instant paranoia. I never felt so disorientated, confused and generally altered as I did on cannabis. Plus, the hangover lingers, a foggy half-life, and they say cannabis stays in your system for weeks. I gave up my sporadic use of it a few years ago when I was 30.

Not that any of this is to say that drug use shouldn't be decriminalised. But why just cannabis? Why not all of it? Legalise it. Tax it. Live with it. It's the only way. In this country, the "war" on drugs started with that piece of legislation in 1916. Eighty-eight years later, we're still pretty much at square one. Far more harm comes to the world through the criminalisation of drugs, and what that means in terms of a black economy and an underclass, than comes from use of the drugs themselves. And anyway, aren't alcopops pretty powerfully mood changing too?

But, then again, if hash was legal, maybe we'd have to suffer ads telling us that we'll pull a cool bloke if we order our Marlboro Lights with added THC. And, oh dear, all that awful cheery packaging and marketing...