Brendan Walsh, 52, a publishing director, is married and lives in London. He gave up drinking seven years ago.

I drank a lot when I was at university and in my 20s - drinking was always the thing I was best at. (I studied medicine; medical students were often big boozers in those days.) I always knew I would grow out of it, though. As I got older - through my 30s - I discovered ways to spend an evening other than down the pub. I found myself in theatres and art galleries; I was invited to dinner parties. I began to talk to girls. I drank less, but age and lack of practice meant the hangovers got worse. I thought about "cutting back", but somehow it seemed easier to stop altogether. I did not see myself as the sort of person who would primly decline a second glass of wine at dinner: drinking is a serious business, and I felt you should either do it properly or not do it at all.

I thought I needed a couple of drinks to relax and enjoy a party, but seven years after giving up booze I find I can keep my end up in a conversation just as well with a fizzy water in my hand. To my astonishment, that little pang of early-evening anxiety that I used to try to quash with a couple of gin and tonics has gone. The scary thing now is that as the booze is consumed around me I sometimes glimpse just that shyness and fear in others' faces that I used to try to drown. One funny thing is that I occasionally wonder just why I thought some of my old mates were quite so fascinating and amusing. A bit of fuzziness around the edges of your judgment oils the wheels of friendship.

I would never get preachy about drinking. Most of the people I love best are drinkers. I comfort them by assuring them that I don't feel any better since I stopped drinking. Secretly, though, I do. Nothing dramatic, but I don't feel the same low-level nagging tiredness that I used to. I wince less often at the memory of a clumsy remark. I go to bed knowing I won't be getting up again in a couple of hours with a splitting headache trying to remember where the loo is.

There is a certain glamour to not drinking at all. If I am offered a drink I usually explain that I have had my allocation. The trick is to cultivate the look of a man who has lived a bit, who has enjoyed a past of debauchery and excess. Everyone prefers the reformed sinner to the lifelong puritan. I am not a teetotaller. I am a person who "enjoys a drink". But I don't want a drink right now, thank you very much.

Penny Jones, 26, a syndication executive, is single, and lives in London. She gave up drinking two years ago.

I used to wake up exhausted every Saturday and every Sunday morning because I had been drinking, and I was starting to think: why do I do this to myself? Is it something I really enjoy? And then I was put on some medication for a month, which meant I couldn't drink.

It was hard at first, because I was determined not to change my social life. So I still went out at weekends and got home at 6am, but I discovered that I could wake up at lunchtime and instead of feeling awful all afternoon, I felt fine and could get on with everything I wanted to do. So after the month was up I thought: why don't I just carry on? And then, when I got to six months, I felt really proud of myself and thought, "I can do this - it's a real achievement".

One of my big worries has been what other people will think of me: no one wants to be thought dull and boring. I usually wait until I know someone a bit before I tell them I don't drink, so they don't make any assumptions about the sort of person I am. But on the whole I've discovered that the people you're out in the pub with don't really notice that you're not drinking: you're aware of it, but they're not.

One fallout from my decision to stop drinking has been that I have lost about a stone in weight. I wasn't overweight, but I am very pleased to have got slimmer: and it is definitely not because I eat less, because I really do enjoy my food! The other thing I have noticed is that I feel more robust in myself, and I don't pick up every little bug and cold going round, though I don't know whether or not that is related to not drinking.

The office party - it's our Christmas one tonight - is always one occasion when I'm really happy that I don't drink. I always used to have that worry the next morning that I had said the wrong thing to my boss or something when I'd had too many glasses of wine: now I know that, whether or not it is the middle of the night at a party, I'm always the real me, not someone who is in a bit of an alcoholic haze saying stupid things. In that sense it has made me feel a lot more confident about myself.

Martin Vrhovski, 29, is single and a cab driver. He stopped drinking two years ago.

I used to be like any youngster - drinking plenty at weekends, and in the evenings. And then one day, two years ago, I thought: I don't need to do this. I didn't like the way it made me feel the next day: I would feel rough, and I like feeling energetic and on top of things. And I did have health worries: I thought, if this is how I feel the morning after, what is this stuff doing to my body?

So I decided to give up at new year 2005: it was a new year's resolution, I guess. But it was not that difficult; I don't feel I am the kind of bloke who has to have a few drinks inside him before he can talk to a girl. In fact, it soon seemed quite an advantage not to have a few drinks inside me, because what I say makes more sense and I don't think it is particularly attractive to be a big boozer.

Then a couple of big events came along, including a 30th birthday party, that really tested my resolve, but once I had got through them I had more confidence to carry on without alcohol. There have not been big health benefits, to be honest; I'm a semi-professional footballer, but I don't think it makes a huge difference to my training. One thing I am pleased about is that I know it is reducing my risk of various medical conditions, and as I get older I think that will be increasingly reassuring. But then again, there are no guarantees: the main reason I do it is because, first, I can and, second, I didn't like the hangovers.

I have tried the very occasional glass of something: when my sister got married I had a glass of champagne, but it lasted me all day. I thought to myself, why not have just the one? But then you start thinking, what is the point of just the one? If I'm honest I don't even like the taste that much any more.