Last week Sir Richard Branson and Alan McGee were amongst people who wrote pieces in favour of decriminalising illegal drugs. They both say they once used them but don't now. My position is different; I'm an addict. At least, I think I am, though not of anything illegal.

The American Society of Addiction Medicine defines "addiction" as "a primary, chronic disease of brain reward, motivation, memory and related circuitry."

Not exactly sparkling clear, but it seems to suggest I might be addicted to quite a few things. To restaurants, to warm weather, and to having a few quid in the bank. But more importantly in this context, to alcohol.

I'm not an alcoholic - it's not my body that craves the stuff, it's my mind. I'm not a lush; I rarely get drunk and slur or fall over. I'm simply addicted to alcohol's eclectic qualities. And I drink some almost every day.

It socialises me, renovates me, uplifts me and sends me off on conversational adventures. It can calm me, reassure me, and keep me company late at night when I'm working alone. And when I'm feeling depressed or lonely, where a well-meaning person would be an unwanted intrusion, alcohol is a perfect friend.

I've never been interested in any other drug of any sort. Despite a lifetime in the music industry I've never sniffed a line of coke or dropped a tab of ecstasy. I've never known acid or hallucinogenic mushrooms; never taken amphetamine, or ketamine, or heroin, or opium. And never wanted to. I've occasionally smoked marijuana but it sets my throat on fire. My drug is alcohol.

Which brings me to the point.

In the West, people's prejudices against drugs, like people's prejudices against race, religion and sexuality, derive mainly from Christianity. For 2,000 years wine has represented the blood of Christ at Holy Communion. As a result, alcohol is the accepted drug of Western society.

As attitudes have evolved, the powers that be in British governance have come to agree that all people are equal, everyone can choose their own religion, and nowadays can even be of different sexuality. But when it comes to using a different drug, they're still not ready for it.

As a rock manager I've spent my life dealing with people on drugs. Most are relatively harmless when used recreationally, but a bloody nuisance when done to excess.

Marijuana is the commonest - friendly enough, but it can slow people down, as can ketamine or Xanax. Keep the drummer off them before a gig or the tempos will drag.

People doing acid should be kept away from windows and rooftops in case they feel a sudden urge to fly - the front of the stage can be dangerous too.

Cocaine pushes the tempos up and if you're not careful the gig can be over before it's meant to be.

Ecstasy makes people annoyingly friendly, which doesn't sit well with rock'n'roll attitude.

And heroin, while having the worst reputation, is comparatively harmless providing your lead singer doesn't get himself arrested while out scoring some and find himself behind bars at the very moment he's meant to be leaping out onstage.

Methamphetamine is the worst. People who take it see conspiracy theories in every corner. Guitarists think roadies are deliberately handing them un-tuned instruments to make them sound bad. Roadies think guitarists are plotting their dismissal, so they deliberately hand them un-tuned instruments.

For the most part, people in the touring party use these drugs with expertise. The show goes on and excesses only occur afterwards. And after 40 years of observing all this I've only one question to ask - if other people can get the same pleasure from their drug as I get from mine, why on earth should they be forbidden from doing so?

I'm not advocating taking these drugs, just saying it's absurd that to do so should be criminal. Their illegality has no basis in logic. Only in bigotry.

In this week's Sunday Times India Knight admitted, as a parent who once took drugs, it's difficult to broach the subject with her kids. She also says, "years later nobody says, 'I loved the years I spent stoned and paranoid on the sofa'."

Wrong, India! I look back fondly at all the times I've been zonked on the sofa with alcohol. All the times I've been high on it, danced on it, cried on it, screwed on it, failed miserably on it, and even damned nearly killed myself on it. I love every single memory.

And if those same memories were in my brain as a result of taking cocaine, marijuana, heroin, ecstasy, amphetamine or opium, I'm sure I'd look back on them with equal fondness. The only difference being - I would have been breaking the law.

Which is absurd.