Coleridge was the one who established the romantic connection between getting wasted on drugs and yet being granted the entree to a deeper reality than the rest of us get to see.

Here in the 21st Century, we tend to think that the drug problem started in the 20th Century, forgetting that it acquired its most insidious element in the 19th Century, with the notion that the world of drugs might be more exciting than the real world. That notion has bedevilled the whole discussion ever since. What do you do if people actually want this stuff?

If the government is still there after the next election, it might eventually want to take the advice which Prof Nutt was apparently all set to offer, which is that cannabis is not so bad after all.

The government might even eventually want to legalise cannabis, or at least follow the example of California, where you can buy it for medical purposes. But suppose one or more of the panel offered the advice that a much more powerful drug, namely heroin, would be less destructive to society if it were made legal?

It's not impossible to imagine that advice being given, and given by an expert, because there was a time within living memory when heroin, in Britain, was legal. Heroin wasn't criminalised until 1968, and when I arrived in London in the early sixties you could still see the famous midnight queue at Boots in Piccadilly, where the addicts gathered to get tomorrow's allowance of their prescribed heroin pills.

The point was that there weren't many addicts. There weren't many in the whole country.

After the drug was banned, however, it became more popular. The gangsters got in on the act, and whole thing escalated until now you not only have thousands of adults shooting up with needles, you have children shooting each other with guns. The reasons for this disaster have been analysed to shreds, but one factor hard to rule out is that it makes a story.

Drugs aren't humdrum. There is danger, special kit, a racy vocabulary, a ritual. That was already true for Sherlock Holmes, whose creator, the physician Arthur Conan Doyle, for some reason equipped the world's greatest detective not just with a super brain but with a taste for the needle.

Way back before World War I, there was an element of the young upper crust that fooled with morphine. It was legal and available, but the fact that older people frowned upon it made it look glamorous to the bright young things.

If you read the diaries of Duff Cooper, you find Lady Diana Manners and her glittering friends getting off on the stuff all the time. Nowadays, however, when the stuff is banned, even the less privileged look glamorous if they are sticking needles in themselves. Nobody would make a movie like Trainspotting if the characters were just holding down jobs and going to the supermarket.

In America cocaine was banned in 1914 and heroin in 1925. Traffic in the banned drugs quickly became a major theme for crime fiction. In some of the pre-war crime movies, and in almost all of the post-war ones, drugs are fuel for the action.

It's been said of modern Hollywood that it's a factory where people high on cocaine make movies about people high on heroin, but somebody must have his head screwed on because people want to see the movie even when it makes drugs look awful.

Back in 1955 The Man With the Golden Arm should have finished off heroin's career as a desirable product - Frank Sinatra got so strung out he could barely react to Kim Novak. Fast forward to the 1983 version of Scarface, and you can see Al Pacino destroy his criminal career with a nose-dive into a pile of cocaine bigger than his head.

But no amount of didactic condemnation from the big screen has ever slowed the trade down, and on the small screen it's doubtful if even that magnificent series The Wire has done much to persuade the corner boys that they would be better off trying to improve their grades.

The Wire is a test case. If you haven't seen it, it's about how the whole black inner city of Baltimore is turned into a war-zone by drugs. It's a tremendous piece of work, The Wire. It's got everything, including a precision of language that you have to call poetic. And it's got an unpalatable message - the war on drugs can't be won.

Decriminalise all the drugs, put things back the way they were before the roof fell in, and you might still be stuck with people for whom real life simply isn't thrilling enough, even when they are otherwise quite good at it.

I think they're wrong, but it isn't easy to make a case. Western civilization is up against it in that respect. Now that religious faith is so weak a force, how do you convince people that ordinary life is worth the effort?

Charlie Parker, the wonderful saxophonist who ruined himself with drugs, tried to tell his fellow musicians that they were fooling themselves if they thought they could play better when they were high.

Few musicians listened to what he said, so why would anyone listen to Nancy Reagan saying "Just Say No"? She sounded so square.