It was a glass of undistinguished white wine, which I didn't even finish, but if I'd known it was the last alcohol I was ever going to drink, I would have chosen something grander - a single malt, a classy rioja, maybe just an honest pint of bitter.

But I was tired. I'd spent the day walking on the South Downs with friends. We'd had a boozy lunch along the way and, arriving back home, I was too tired to go out. I didn't bother to eat, just that glass of wine before turning in. It was, I subsequently realised, midnight on the 12th day of the 12th month, 2001 - my own private armistice.

Four hours later I was lying in intensive care being pumped with morphine. I remember thinking how I'd always wanted to have morphine but not like now, to assuage pain. And what a pain it was that had woken me at 1.30am - like a mad animal trying to burrow its way out of my abdomen. Women who have had both a baby and acute pancreatitis routinely say the pancreatitis was more painful, a fact I am storing up for next time a female friend declares: "You men don't know what pain is."

It's mostly men who get this disease. In some cases the cause is unclear; in some it is gallstones, but for the majority it was the booze what dunnit. The fact that I was persistently asked during that first night, "How much do you drink?", suggested what the doctors were thinking. I sensed very early during my three days in intensive care that, at some point soon, a doctor was going to say: "You'll have to give up alcohol."

Part of me felt hard done by in a way because I know plenty of people who've drunk more than me over a longer period. And I was a pretty good drunk - not aggressive or maudlin, but loud and amiable, liable to take fellow barflies on adventures. Every Edinburgh festival I would lead a boozy late-night walking tour of the Royal Mile - which got big laughs and the occasional arrest. I always got home at the end of an evening, always cleaned my teeth and got my clothes off before I got into bed. As a drinker I had created fun, if not for my neighbours, then for whatever entourage I had acquired. It was in drink that I introduced several couples who are now married, and many others who just paired off for the night. Oh me, I was a marvellous bacchanalian figure, wasn't I?

I didn't much feel like a Roman god, sweating away in agony at St George's hospital. My last visit there had been in the early summer when I had gone to casualty with a flayed elbow, acquired during an attempt to carry a woman on piggyback across a gravel car park. I could have succeeded if I had not been drunk, but then of course if I hadn't been drunk I wouldn't have tried it in the first place.

This time was a lot more serious. Not all that many people die of acute pancreatitis but if, like me, you have the necrotic version (where some of the pancreas dies) then the mortality rate is so high that I can't bring myself to write it down. When I came out of hospital people asked me: "Did you think you were dying?" I said no, but I certainly knew this was a Big Thing for me, and I dimly remember thinking that perhaps death would be preferable to this pain; it only began to dawn on me how serious the attack was when I saw it written on the faces of my family and friends.

I'd never visited an intensive-care unit before, let alone been a resident in one. It was, as you would expect, sombre and full of intimidating- looking machines, several of which I was attached to. A doctor told me that the NHS budget was £1,500 per night per person for a spell there. It must, by some measure, be the most expensive gaff in Tooting and, at the same time, the one you'd least like to stay in. I was observed full time to see if my angry pancreas had lashed out infectiously at the rest of my body. To try to avoid this, various organs were given a bit of time off, which involved tubes being inserted in me, wires being attached to me and an oxygen mask clamped onto my face. During the long nights a nurse would sit at the end of the bed monitoring me at what looked like an enormous Hammond organ. No one ever really told me exactly what was going on but I wasn't entirely sure I wanted to know, so I didn't ask.

Ignorance can be good for optimism and once my pain (and therefore, I presumed, the attack) began to abate, I immediately started to feel stronger and eager to proceed as swiftly as possible to the point where I could step out of the hospital and breathe the sweet outdoor air of south London. I was impatient not to be an in-patient. Yet I was to hear the dark phrase, "You're not out of the woods yet" several times over the next few injection-filled days, and I began to resign myself to the fact that the doctors knew more than I did.

In the end I spent 12 nights in hospital, the last week on a regular ward where for the final few days I was attached to nothing at all except a fierce desire to leave the boredom, miseries and petty indignities of life on the ward. Those marathon nights when you can't sleep because you've been lying, snoozing all day - except you're not really snoozing, you're just wishing the hours away and fretting that you might be due a relapse. My heart goes out to the poor chap opposite me who, even as I write five weeks later, is still lying there with his shattered leg. He is a true stoic - I never once saw him even attempt to read a book or listen to a Walkman. Having found these distractions not distracting enough myself, I had rented a TV on a daily basis from "hospital entertainments" but even the football seemed far away and uninteresting. Of course I had visitors but, for everyone's sake, never for too long.

It was the drink that brought me to this just as it was for millions of others. And yet I felt no anger at alcohol, I was not inclined to issue a lawsuit against Young's brewery or fret about all those stupid nights when I should have gone home earlier. (A friend staying with me found a note one morning saying "6.15am - why is it so late and so pointless?") I'd had some good times, and even some inspirational ones. Drinking was a part of me.

Perhaps you're bored by my posing as a heroic pisshead. I am a bit. The fact is that the booze had begun to dominate my life over the past few years. I was starting earlier and finishing later. I'd drink heavily after (and if I was compering, during) performances that I gave. I'd acquired a taste for vodka - the drinker's favourite - because it doesn't really taste of anything. And then there were the hangovers... but enough already. Better writers than I have much grislier tales to tell of their booze hell which make my own caperings sound more like booze heaven.

Those woods in which I stayed, I'm still not out of, but I think I can see their edge. In a month I will have a scan, which should reveal what's happened to my dead section of pancreas. An operation may be necessary. Another attack is possible and would be bad news. There are other potential complications which my redoubtable doctor, the flamboyant Mr Fiennes, was happy to outline to me, even, if I wanted, by email. But I decided I'd got enough answers to be going on with. I could spend the rest of my life considering what may end my life - my computer offered 35,700 entries on "acute pancreatitis" - but it seems healthier just to be in the world as normally as possible. In my case this is very normal indeed, since the only thing that I've really had to change about my life so far is the drinking.

In the pub, friends were appalled and fascinated by my having to give up alcohol - their sympathy tinged with concern for their own innards. It could have been me. It could be me. In some I detected a certain disappointment when I tell them smugly how easy I am finding it. And I am. There is no incentive for staying sober, I say, like the prospect of dropping dead if you don't.

As these friends around me reach their second drink, I light a fag (all right, I admit it) and see that flush of pleasure that comes when the alcohol kicks in. I envy them, but not much, and it's fine. I tell them what I call my last drinking story. In intensive care I was, for three days, "nil by mouth". During that time I was on a drip, which did not prevent me developing a craving for a glass of water. Not allowed. Sorry, not yet. Finally, after I had asked about a thousand times, I was given one. No drink, alcoholic or otherwise, ever tasted sweeter than that little paper tumbler of water. By now, in the pub, I hope I'm losing their interest - I know I'm just some other reformed lug with a tale to tell. As they get the third drink in, it's time to go since there is no non-alcoholic drink in a pub that's worth more than two glasses, and, as I had always been told, it's a bit boring being sober among the inebriated. They warmly wish me well, and I leave them to it.

The virtues of sobriety are well known, but interesting to a novice such as myself: I have been more clear headed and intellectually alive than I can remember, while my day has shifted forward two hours, leading to the rediscovery of the possibility of mornings. My scary adventure has produced many positive things and they're the ones I'm concentrating on, and I concentrate well at the moment. Every day has a newfound intensity, which makes me welcome the winter cold and rain onto my cheeks.

I have bid goodbye to Arthur the drinker, made a speech, put him on the boat made of beer mats and sent him off down the river. Now I wake every morning to a soppy mantra in my head: "I'm alive. I haven't got a hangover. Fantastic."