He could have been a footballer.

His father was a footballer. In the field behind his home in Robroyston, Glasgow, he would try to impress Michael Jamieson Sr with his skills, zig-zagging between cowpats to control high balls with a deft touch. But he chose to do something else, and it has paid off spectacularly.

To the casual observer, a sportsperson who rolls out of his driveway in a BMW with a model in the passenger seat is, in all probability, a footballer. But Michael Jamieson is a swimmer, and he has come to this enviable life along a path that was never obviously paved with gold. This is not a tale of premature privilege and easy money but one of riches mined through single-minded and often solitary sacrifice. It has been a glamourless, monotonous series of laps up and down a pool.

The stars have aligned to bring this story and this 25-year-old to our attention. On Thursday night, Jamieson, not yet a household name but on the brink of becoming one, intends to give Glasgow a hometown champion to cheer on the first night of competition at the Commonwealth Games. Not only that but he intends to win gold in a world-record time, which would make him the first Scot to set a world record since David Wilkie in 1973 - also in the 200 metres breaststroke. He will be chasing a second medal in the 100m on Saturday.

Jamieson was born and raised in Glasgow, and this only adds to the riddle. Why didn't he just play football like everybody else? Although Milngavie and Bearsden produced Alison Sheppard, who swam to Commonwealth gold for Scotland in Manchester in 2002, this year's home team will be disproportionately short of Glaswegians. Besides, Jamieson is not just making up the numbers; he is a world-beater, an Olympic silver medallist and the fastest 200m swimmer on the planet this year.

Some of the rivals Jamieson will come up against over the next week at the Tollcross International Swimming Centre will have been water babies, invited to swim in their infancy as an alternative to sinking. Jamieson's initiation, at the age of five, was somewhat more sensitive.

"It was at Springburn Leisure Centre, a little, dingy pool, and my parents bought me a six-week Learn To Swim block," he tells me when we meet in Bath, where he now lives. "It was just a little introduction, basically learning how to float and be familiar with the water, and I didn't like it at first. I just didn't like being cold and being in the water, and I didn't actually get in until the sixth and final week of that block.

"It was only 30-minute sessions, and I used to walk along the poolside and decide I didn't want to get in because I didn't want to get cold, and then go and stand in the shower for 20 minutes. My dad would sit outside and wait for me, and he knew. In the car on the way back he would say, 'So, you not fancy it again this week?' I would say, 'Nah, I'm not ready for it yet.'

"I think the primary reason behind my parents getting me involved was just that it was a life skill. When I did actually get in, I loved it, and I just started collecting my badges from there. I could swim 25 metres and then 50 metres, and it was all about getting those badges sewn on to my club swim bag. I moved then to Scotia Amateur Swim Club in the Leisure Drome in Bishopbriggs, swam there for a few years and then started competing. Aged 12, I applied to go to the Glasgow School of Sport and, in conjunction with that, I moved to City of Glasgow swim team, a really big age-group programme. That was it, really. I decided then that, by getting into that school, this was the career I wanted."

Aged 16, all skin and bone and pent-up potential, Jamieson moved to the other side of the country to train with the City of Edinburgh Club. Four years later, fearful that all his hard work might go to waste, he followed the club's coach, Fred Vergnoux, to Paris and lived, penniless, in the most cramped accommodation imaginable outside of Her Majesty's Pleasure. "In Paris, I didn't have the money to live," he recalls. "I had to save up to go to the laundrette to get my clothes washed."

Jamieson's next move was to Bath, where the university is a hothouse of British swimming talent, and where he now owns a valleyside coach house on the edge of town . He runs a nice car, provided by the Harry Fairbairn dealership in Glasgow, and has a raft of blue-chip sponsors. He is not as wealthy as he would have been had he played for Celtic, but he is comfortable, and he has earned the right to be.

Handsome, with a body that suggests he went out to get a six-pack and came back with four extra free, Jamieson has also become quite the catch. Settling down with a girl was never a stated priority but, when attending last year's Scottish Fashion Awards as a guest of Tom Morris, he met Glaswegian model Gillian Cook, who has graced catwalks all over the world. He is permitted the occasional weekend off and the couple attended music festivals in Bristol and Bath in the weeks before this interview.

After the angst and intensity of his formative years, Jamieson has at last learned to allow himself to live, without it compromising his training. Olympic success has changed his life and it would be natural if that led to a change in the man, but this is not going to happen. He is grounded as if glued to his roots, to the rules of Robroyston and the values instilled in him by parents who would have lived on Mars if it would have helped him fulfil his potential.

So if all goes well on Thursday night, and he finds himself scanning the crowd from the podium, the faces he'll be searching for will be those of his mother Jackie and his father, who played professional football for Hearts, Stenhousemuir and Alloa Athletic, and his younger sister Lauren.

"My dad has so many regrets about his own football career," says Jamieson. "He's a huge sports fan and he loves the idea of pushing yourself on a day-to-day basis and the process it takes to get the results you want. So I think that was instilled in me from a pretty young age. My mum's similar to my dad in that respect, so I was surrounded by that.

"The number of times my dad told me, 'I wish I could go back and have my time again as a footballer ...' and, 'If you've got some talent here, you make the most of it.' A lot of people have regrets, especially athletes, and I know my dad isn't envious of me, because he loves to see me doing well, but as an ex-athlete he knows how amazing it would have been to have the kind of guidance and coaching I have had."

It was while he was in Paris that Jamieson first became aware of the stress his parents were under, in order to keep him there; and that moment was a turning point in his career. "I was aware that for me it was a last throw of the dice and if I didn't qualify for funding I would have to walk away from it, because I was 20 years old and wasn't at the level I wanted. Coming back from that and seeing how much they were struggling to keep me out there, that was when I said, 'This is it, I'm not missing out on any teams again.'

"I'm so grateful for everything they have done for me, and my sister as well [Lauren would often be bundled into the family car at 4.45am when young Michael was being driven to Tollcross for training; she is now a dancer with the Urdang Academy in London.] I think that's why the last couple of years have been so special because everyone has been a part of it and could see it all come together. I'm hoping to have everyone there at Tollcross and put the icing on the cake."

As we drive around the hills of Bath, Jamieson recalling how his old one-litre banger used to struggle with the steeper ascents, I ask if he has ever frequented the sumptuous Roman baths for which the spa town is famous. "I have been once, but it's an expensive day out," he says, confirming that the boy's extraction from Scotland has not come at the cost of his Caledonian prudence.

Jamieson describes the Glasgow Commonwealth Games as the biggest event of his career to date. Very few who took part in the extraordinary London Olympics would be taken seriously for saying that, so why does it mean so much to him? "I think everyone has a sense of identity and pride over where they're from," says Jamieson, "but Scots would always say that it's a bit stronger there. And I think it is. It's obviously a pretty small but very proud nation. In many aspects, especially in sport, we punch far above our weight.

"I'm always going to relate it back to sporting terms, because that's the only world I know, but I think there is a fear of failure there which is looked at positively. If I think I have a skill set that can take me to the top level in any field, then I'm going to work as hard as I can to get there, and I think that's present in Andy Murray, in Chris Hoy, in the Scottish judo players who have had some amazing results in the last 10 years or so.

"There is no real reason why we should be at the top of the world in sports like that, but I think there is something a bit deeper than talent and ability that's there in Scots more than others. We're just willing to do what it takes to get the results you're looking for.

"I think it's a Scottish thing in general that if you have a bit of potential or ability then you make the most of it. I've never really had a safety switch when it comes to training, I've never had the ability to say, 'That's enough,' and in the past few years that has caused me to get a few injuries. I haven't really known when to stop and that little heart thing at the turn of the year is the best example of that."

Yes, you read that correctly: "That little heart thing." In December, Jamieson was taken to hospital after his heart rate rose to maximum levels during a training session and then began to beat erratically. His heart was restarted to restore its rhythm. Later, a heart specialist informed him that he'd only seen this condition in a handful of patients - all of them Olympic medallists.

Eilish McColgan, the steeplechase runner and daughter of former world champion Liz McColgan-Nuttall, was recently treated for a similar condition, but we have been repeatedly assured that Jamieson's overworked ticker is not a cause for concern. He has certainly refused to allow anxious thoughts to invade his preparations for next week's homecoming at Tollcross.

"I just keep reminding myself that this is the position I wanted to be in. I wouldn't be human if I didn't have a few little panics about it, worrying about the pressure and results, but I think that's totally normal and whenever I feel that coming on, I just think back to five years ago. If you had asked me then if I wanted to be in this position or not, obviously I would say yes," he reasons.

"I'm in this sport to win medals, and this is just one of the things that comes with it. It's brilliant. The pressure is the result of a huge amount of support, and I would obviously rather have that than not have that. I've said I want to take on that responsibility, I'm competing on day one and people expect me to do a job and I want to be seen as a bit of a leader and help get the team off to a great start.

"For nine, 10 years the only thing I thought about was getting a medal in 2012. I had just decided that was my year because I would be 23 then and coming into my peak. To think of that one thing for so long and for it not to come off would have been pretty devastating. In a way, I think that's how it has worked out for me. I've never had a Plan B." n