Frank McFadden is not one of those people who swish slowly and silently around exhibitions. He is dashing between the pillars; up and down the stairs at Kelvingrove Museum and Art Gallery, Glasgow, like an Andrex puppy. Before we leave, he walks over to his favourite sculpture - ''well, my favourite after those two in Rome'' - and is not frightened to stroke it.

''Look at her. Look at that fleshiness - those delicate bones,'' he says in a thick Glaswegian accent. He pretends to flick the backside of Syrinx. ''You would think if you hit it, that it would wobble.''

Anyone who knows McFadden would realise how good it is to see him like this.

During the nineties, his family watched him spiral downwards from being a promising graphic artist to an unemployable drug addict whose only hope of getting his life back together was through selling The Big Issue. During the ten years that McFadden was addicted to heroin, he considers himself to have been dead and describes how he has spent the past two years coming back to life. These days, he coyly calls himself an artist, because one of Britain's most established artists tells him he should.

If McFadden makes any money from his art, you could call his story the ultimate rags-to-riches tale. It was in a coffee shop on Great Western Road in Glasgow that he first spoke to another Glasgow artist, Peter Howson. Laughing, McFadden describes how he would hang around cafes in the city's West End hoping to meet a famous artist, any famous artist.

Howson was the first one he spotted. ''I knew his work because I used to stare at a poster he'd done advertising the Don

Giovanni opera, with all these intertwining bodies, and I thought it was blindingly good,'' says McFadden. ''But how I knew who he was, I really don't know. I was nervous, but I made myself talk to him. I'd seen him in the cafe the day before and I'd missed my chance. I wasn't going to do it again.''

Howson arranged to meet McFadden so he could see his artwork. McFadden took everything. His school drawings, sketches he did while working as a sign writer, college competition entries and the suicidal pastel pieces from his ''dead'' period, depicting heads on plates and grotesque monsters. Howson said it was the best work he had seen in years.

Today, McFadden looks fresher than ever. He leads us into the studio he now shares with Howson bouncing, not walking. Howson is on the phone, as usual, and a little flustered. Without being asked, McFadden is running around for the photographer like a dog on fire. It quickly becomes apparent why he describes himself and Howson as being a bit of an old married couple.

''Frank, could you get that?'' Howson says on hearing the fourth call in ten minutes. McFadden takes a message and then continues to talk to Howson's caller. And talk and talk. ''Frank, could you get off the bloody phone? I'm trying to do an interview here,'' begs Howson. He rolls his eyes at me and says, ''Honestly, he drives me mad sometimes. I think it's part of his charm.'' Then McFadden leaves to give him some space, and Howson spills the truth. ''Frank just blew me away. He's the best artist I've come across in ten years, maybe longer,'' he says certainly, firmly, proudly. The best you've met or the best artist among the up-and-coming? The best you've discovered yourself? The one with the most potential? ''No, just the best artist.''

It's quite a thing to say. In his time Howson probably skimmed politely through hundreds of portfolios. ''When I look at all the peely wally efforts I've seen and compare them to the strength of Frank's, you can see he's got it,'' he says. ''It's honest, strong and has great

spirituality. I truly believe he is a brilliant

talent. He's not done a lot of painting yet, but I'm not too worried. He's coming along nicely.'' It's not just the spark. Howson likes McFadden's attitude.

''I once saw him in Costa Coffee before we properly met, and he never saw me because he was so engrossed in a sketch. It was a joy to see. He's a great draftsman - a natural. He's not greedy, either. Most art students I've met recently are desperate to make money, but they don't necessarily have enough talent to back that up.''

Art is not the only force that has propelled McFadden and Howson together. They have experienced similar troubles. Both have fought off addictions and struggled to be good fathers. ''Although Frank was a much better father when he was an addict. I was useless,'' says Howson.

In 2000, Howson reached his lowest point. He was nearly bankrupt, and his drinking had almost destroyed his relationship with his daughter, Lucie. He could barely find the energy to paint. When McFadden was asking his doctor if he could be placed on a methadone programme, Howson was checking himself into a rehabilitation clinic at Castle Craig in the Borders and deciding to devote his life to Christ.

McFadden and Howson were taken aback by the similarities in their work - the same gruesome intensity, and the same obsession with faces, figures and religious imagery. ''Apart from all that, I got a good feeling about Frank,'' says Howson. ''I like him. We've got the same sense of humour. I love having him around. He's a fine human being.''

Minutes later, McFadden is back and they are reminiscing about their tomfoolery on train journeys to Derby, where Lucie, aged 17, who is autistic, attends school. They howl about Howson's demanding guinea pig, which eats organic carrots only, and indulge in some Carry On banter. McFadden is still treating their cramped studio like a Formula One track. ''So hyperactive,'' Howson sighs, chuckling. McFadden and I slink off somewhere he can be hyperactive for the duration of an entire packet of Embassy Regal.

As he jabbers away fluidly in a dusty, dimly -lit coffee shop, it becomes apparent that McFadden's frenetic pace is down to a brain permanently crammed with thoughts. Life has changed quickly, and he is still trying to adjust to his radical U-turn.

Francis Gerard McFadden's childhood began 33 years ago and 12 floors up in Trossachs Street, Maryhill. He lived with his mother, a care worker, his father, an electrician and his brothers Gerry and Michael. When he was 12, the family moved to the tenement flat where his parents still live with McFadden and his sister, Joanne, now aged 15.

''I even enjoyed school,'' he says. ''I just thought the whole thing was a brilliant laugh. I wasn't a bad boy, but I'm sure I got up some teachers' noses because there was always too much carry on. I'd say I was a cheeky monkey rather than a disruptive element. I was preoccupied with laughing, which has probably always been my biggest problem. You have to get serious at some point and stop shirking your responsibilities, because if you don't, all hell breaks loose.''

At Pope John Paul II Academy, McFadden began to raise eyebrows rather than hell when he flashed around a portrait he had done of his teachers - an ''honest work'', he says - in which the overweight teacher was overweight and the pregnant teacher was pregnant.

Seeing beyond his japery, the depicted teachers repaid the compliment by entering his work for every art competition he was

eligible for. He won most of them.

He left school at 16 with decent grades, including an A in art, and began an apprenticeship as a sign writer, simply because it had the ''element of artiness'' he craved.

''The way I saw it, I wasn't able to draw because I was great. I could just do it. It was a gift, not down to anything I had done. There's a responsibility that goes with that, and I had no other choice but to pursue it. That has always, always been at the back of my mind.''

McFadden had decided not to apply for art school. ''It smacked of more study and I really wanted a wage,'' he says. ''All my mates had gone on to become mechanics and plumbers. It was a blunder, yes, but I don't look at it that way.'' Like Howson, he is a firm believer that nothing ever happens by chance.

The five-year apprenticeship was, he says, ''a good laugh'', but as a self-confessed technophobe, he acknowledges the early nineties was a bad time to enroll in a graphic design course at the Glasgow College of Building and Printing. Drug culture interested him far more than computers.

''I didn't become a manky junkie straight away,'' he says. ''It was like Apple Mac came in at one side and drugs came in at the other. The course was a doddle, and really didn't inspire me, so for a while I was just a party animal, taking a lot of uppers and travelling to England to see the Happy Mondays, The Farm and Stone Roses.''

Minutes after McFadden mentions this, the stereo system of this quaint Italian eaterie begins playing the Stone Roses' Greatest Hits. When McFadden talks about predestination, you can understand why he is so convinced by it. His story is strewn with coincidences, such as spotting Howson in a coffee shop the artist rarely visits, and seeing him again there the following day, even though Howson would also not normally visit the same cafe two days in a row. That one throws him a bit.

''I can't listen to all that Manchester

explosion music any more. I associate it with too much.'' He shakes his head and pulls out a cigarette. ''You know, I'm the kind of guy who would run up and down the street naked if you dared me, but when it came to girls and

dancing I had a lot of teen angst. E blew all that away. I was swinging; a cross between John Travolta and Max Wall. I wasn't rebelling, I thought I was tasting life. I had this philosophy that I would try anything once. But some things you can't just try once, and that's when it all went f**king pear-shaped.''

Here, things get sketchy. He was 22 and in his last year of college. He was living with his long-term girlfriend, and, he says, really loved her, but was soon ''in love with heroin, too''.

At some point he began needing his drug every day. He can't say when. He tried to work during most of the decade, initially as a sign writer, but would sometimes get himself sacked from jobs in order to claim benefits. He would survive taking pill-form opiates for months on end to avoid having to hunt for street heroin and disturbing the working day with trips to the bathroom.

He makes no claim to having experienced the dramatic conversion Howson had, but gives credit to a higher power for his seemingly miraculous ability to clamber out of the depths. Landing a temporary job painting pop and rock heroes on the walls of Tower Records, he says, was ''just typical of my jamminess. We had a blank cheque book to go and buy art materials and could paint what we liked''. He was sacked after being caught trying to steal 24 CDs taped around his waist. That the case against him fell apart in court was also, he says, ''just pure jamminess''. ''I can see I've had a graced life,'' he says.

It has taken a while, though. In 1995, McFadden married and his daughter, Frankie, was born. Even then, those who weren't alarmed by McFadden's extensive weight loss believed his life was peachy. ''By then I was well and truly addicted and they believed the facade. The wife, the child, the job, the house.'' He was even given a bank loan to buy a Mini so he could go on family excursions. ''I wish I could say that I stopped taking heroin the moment Frankie was born, but I can't. I knew fine well it was a terrible situation for her and I tried to keep working and take some responsibility. My poor mum would bail us out all the time with money. That woman has been amazing.''

Then McFadden was involved in a five-car road crash serious enough for him to have to be airlifted to hospital. He had taken a job delivering fruit and, exhausted by an early morning start, had fallen asleep at the wheel. ''I could have wiped out whole families. I felt absolutely dreadful. I got away with a broken nose.'' Shocked by the experience, he quit his job and began working sporadically, calling on old friends for more sign-writing work. He remembers being sacked from jobs regularly, sometimes after a few days of work, sometimes after a few hours.

By 1998, McFadden was unemployable. His marriage had dissolved and Frankie was staying with her mother. ''My mum was doing her best, getting me on waiting lists at the doctors for treatment, but this was rock bottom. I did want to get off heroin because life was chaos. It wasn't a life. I was thoroughly depressed and the only thing I wanted to do was lay down on the sofa and die. And let me tell you, if you lie down and hope to die, it's so f**king annoying when you don't.

''You're just lying there with your eyes open. Whether it's raining or sunny, you don't know. If you close your eyes you just see wee bags of heroin and tin foil and equipment. You just fantasise about drugs that you haven't got and it's torture. I would sooner pluck my eyes out with a spoon than go through that again.''

A year later, he had pushed his mother's patience to the absolute limit with his scrounging and found himself touring the city's hostels. ''Absolute pits of hell, that's what they are,'' he says. ''I was brought up knowing lying and stealing were wrong, which was why I began selling The Big Issue. The only alternative was crime, and I knew how rubbish I was at that. Not crafty enough.''

Dressed in baggy combat gear and armed with all the joviality he could muster, he would sell the magazine on a corner of Buchanan Street in Glasgow, telling anyone who would listen that this was not where he wanted to be. Back then, his hair was long and shaggy and he could hide behind it if he happened to see someone he knew.

''In some ways The Big Issue restored a bit of pride,'' he says now. ''The fact that people selling The Big Issue are standing, not sitting down on the pavement, speaks volumes. But my problem with it was that I didn't want Frankie to get bullied at school because her dad was selling The Big Issue. I told her I was sign writing.''

If his pride was not fully restored, his hope was. As often as he could, McFadden would advertise his artistic abilities, wearing jeans covered in sketches of intriguing, furious

figures on the days he worked on the streets. McFadden has no idea why he draws so many faces. ''I always wonder, if I paint the face of a person I've never seen, then who is it of?'' he says. ''If I trawled the planet would I find someone like it? I used to think all those

people lived in my head, but they don't. They just appear at the end of a brush.''

His first attempt to deal with his addiction on a methadone programme merely enabled him to carry on his pursuit of heroin at leisure. Then one day two years ago, less than a week after his mother had returned from a trip to Lourdes, his craving for heroin disappeared. ''What I mean by that is the mental cravings,'' he explains. ''Something happened and the real addiction disappeared. I quit at The Big Issue on the same day.

''I really didn't know what to make of it and I thought at first that God might be playing some kind of sick joke and that I could come crashing down any minute. But I didn't. I know that might sound like I've become some sort of a religious nutter, but I haven't. I'm just becoming a good boy again, really.''

McFadden has been on the same methadone programme since. ''It deals with the physical symptoms,'' he says. ''I've been reducing it slowly over a long period of time. It's never gone stagnant, it's never gone backwards and I'm about to drop off it completely in a month or so.'' Some days are easier than others. His energy levels fluctuate and he sometimes finds himself panicking over

nothing. Although Howson hates to see him without a smile on his face, he understands that, sometimes, McFadden will need a quiet day with his own thoughts.

''I think it's because of all the real life rushing back in,'' says McFadden. ''Instead of all my feelings being controlled by drugs, I'm having real feelings and I don't always understand them. I usually can calm myself down by reading something.'' Such days are happening less and less. Even before McFadden met Howson, he had begun to take small local commissions and had started taking care of his appearance again. ''I went mad in the

charity shops,'' he says. ''It's a bit superficial, really, but it gave me a boost.'' Now he is living with his family in the house he was raised in. He has even started drawing women, having avoided them almost completely - as subject matter and company - for years. ''Things have been going so well that I think life would be going great even if I hadn't met Peter. But not this well.''

He did meet Howson, though, and the rest may well be history. Howson is rushing around organising the opening of his new show - an exhibition of religious paintings - in London on April 11, and working furiously to complete his Stations of the Cross, a private commission for a chapel. But in the back of his mind is another important exhibition - he

and McFadden are to have a joint show at

the Lloyd Jerome Gallery in Bath Street,

Glasgow, during August.

''Big Peter and wee Frank on the same walls - I'm really looking forward to it,'' says McFadden. He might only be five foot six and Howson towers over him at six foot one, but one day, who knows, the difference in stature may be no more than a physical one.

''No, I'm sure it will always be big Peter and Wee Frank,'' McFadden argues, laughing and stubbing out his last cigarette. With his track record for jamminess, don't count on it.

Peter Howson's new show starts on April 11

at Angela Flowers Gallery, London. The joint McFadden/Howson exhibition, is planned

for August at the Lloyd Jerome Gallery in

Glasgow. Howson's new work, Phoenix, will be showing as part of the Sanctuary exhibition on April 10 at the Gallery of Modern Art, Glasgow.