THE first time that the Commonwealth Games came to Scotland, in 1970, swimming was the poor relation; athletes were the rock stars.

There was a solitary bronze medal won in the pool, by David Wilkie, but four golds and eight medals in athletics marked a golden age which has never been repeated. The tide now flows swimming's way, and this year that sport is distinctly the more likely source of medals.

Wilkie, 44 years on, still swims daily and will be in the heat of the action in Glasgow, as a legacy ambassador and commentator. When we caught up with him, he was self-deprecatingly at ease with fame and fortune. "I was just a guy who could swim faster than others," he said.

He did that to most telling effect at the Montreal Olympics. His gold in the 200 metres breaststroke was the first by a UK male in 68 years. Michael Jamieson's silver in London 2012 is only the third individual medal won by a Scottish swimmer since. "I was fortunate I was the only individual gold medallist in 1976," Wilkie acknowledged. It presented opportunities in "the dawn of commercialising of sport, and I had the field pretty open to myself".

His world record in that event survived for eight years, by which time he had retired. "I had to get out of my sport at 22 - probably at my peak - to actually make any money out of it. I did relatively well in commercial terms and that lasted about 25 years: working for adidas, arena, STV, ITV, Scottish Electricity, writing books, opening swimming pools, Butlins, Pontins.

"It was actually quite fun, but I recognised that I could not do that for the rest of my life. I had to make a decision about my future based on a real job, rather than old man Wilkie still teaching swimming in holiday camps at the age of 59."

And so, shorn of the trademark long hair, balding but still with his moustache, Wilkie lives an enviable lifestyle in rural Surrey with Helen, his partner and mother of their two children. He describes her as "my wife-to-be. The mind is made up; it will happen at some stage."

He is a millionaire from his sale of a nutrition company and has several business interests: a directorship in Pets Kitchen (a pet food company which retails in major supermarket chains) a veterinary clinic in Swindon and the London property market.

"I was fortunate enough to sell my company at the right time and made a few bob out of that. I invested in property, and buy and sell property. I've been lucky to be in London where the market has just gone absolutely crazy, because all the Russian, French, Arabs, Chinese and Indians are buying up.

"Work occupies eight to 10 days a month and I waste the rest of my time doing nothing; travel is one of my hobbies. So a typical day would be: up, on the computer checking things out and writing a few emails.

"I'm a member of a club where I live and, when I am on holiday, there's always a pool or an ocean, so I am in the water somehow, somewhere, every day. I just got back from Sri Lanka, swimming, snorkelling, diving; it was fantastic fun."

It is where he was born. His father was a tea planter there and David and his sister were in the water daily as children. The transition to serious Olympic training was a culture shock, in which he was eventually covering 20,000 metres a day, six days a week: nearly six hours in the water every day.

Wilkie was still a pupil at Daniel Stewart's College in Edinburgh when he swam in his first Commonwealth Games. As he put it: "I was a quiet rebel, with the long hair. I didn't always take the administration, headmaster or the boarding school as one should. But we were all rebels in the seventies."

Truth to tell, the teenage Wilkie had no empathy at all for swimming. His coach even bought him an alarm clock in a desperate attempt to get him to turn up in time for training. The talent was evident. The work ethic was not.

Wilkie's attitude was reflected in a comment from his coach. "He said I was reading the Beano behind the starting blocks before the final in Edinburgh. I don't think that's true. If it was, I think I'd remember it. But I was a total amateur. I mean, I was 16 and didn't even really like swimming and there I was competing for Scotland.

"I had that immature, couldn't-care-less attitude. When I won the bronze, it was a big surprise to myself and a lot of other people, but it still didn't endear the sport of swimming to me. I wasn't ever an ingrained swimmer till I won silver in Munich and went to America.

"The whole swimming set-up then was totally amateur, and produced amateur swimmers with a really amateur mindset. And I had a really amateur mindset. Coaches in those days, though they were pretty good coaches, also had an amateur mindset. They tried to dominate swimmers and couldn't let them think for themselves. I didn't enjoy swimming and didn't get much out of it until I was 16."

There was no lottery then. "My lottery was the University of Miami. I was fortunate to get a scholarship. The professional aspect is great. In London 2012, Britain would not have had that level of winning [which the team achieved] but for funding; the evidence supports the notion that good funding equates to success. Yes, I am a little jealous, but was fortunate to have Miami as my lottery."

He has compelling logic for his belief that he would not have swum at the level he reached without going to the United States. "What America brings to the party is the level of competition. You swim against the best swimmers in the world week-in, week-out.

"It hones that competitive spirit and gives you the belief that you can beat the best. So, when it comes to the Olympics and you have beaten them in their own backyard, you can beat them at the Olympic Games."

He went to Florida to study marine biology. "I'd spent my childhood in the Indian Ocean and was always intrigued by water, fish and coral. Jacques Cousteau was my hero so my aim was to be somebody like him. But I couldn't hack the course at Miami. It was too tough." He completed a degree in mass communications law after his swimming career was over.

When he won the 200m breaststroke it was the first Olympic gold by a British male swimmer for 68 years and the only men's title in Montreal which the USA did not win. He is the only swimmer to have held UK, US, Commonwealth, European, World and Olympic titles simultaneously.

His entrepreneurial streak was established early. He pioneered integrated cap and googles, using a cap of his mother's and old sports goggles, at a meeting in Canada in 1969 before he had won anything. He patented them with Speedo who sold some 40,000 units.

"It earned me royalties for a couple of years, but it wasn't a great product. It leaked a bit." Now he is investigating possibilities for a cap using newer technology with a Taiwanese company.

It was assumed that his moustache was inspired by Mark Spitz, winner of seven golds at Wilkie's inaugural Olympics in 1972. "Not at all," he insisted. "It went with school, the rebel base and the long hair." It also created another image: "Roger Black [Olympic 400m silver medallist in 1996] told me his wife used to fancy me 'because you looked like an American porn star'."

He is critical, even contemptuous, of today's celebrity culture. "In my era, you were not stuck on a huge pedestal, yet you were revered as an Olympic champion. People kind of regarded you almost as a friend. You didn't have to protect yourself, worry about nutters, or being ridiculed or spoken down to. Or have social networking trying to destroy you: build you up and then bring you down.

"You did not have to be somebody you did not want to be. Now celebrity seems almost forced. People are celebrities because they read the news or the weather, or have been on TV. It's a strange level of celebrity now. It doesn't last; for 25 years I was able to maintain a fair standard of so-called celebrity yet I never classed myself as one. I was just a guy who could swim faster than others.

"I am not demeaning people, but look at Big Brother and reality shows; where do they come from? Who are all these people and how long will they last? I am probably among millions who don't know who the hell some of them are."

He is almost as frank on his sport's under-performance at the London Olympics. He absolves Jamieson, who won silver in the 200m breaststroke with a time eight seconds faster than Wilkie's in 1976, from blame. He backs him to win gold in Glasgow this year, but added: "We suffer, sometimes in this country - and it was highlighted in 2012 - from a mental deficiency: we can't hack the pressure.

"Jamieson surpassed his best three times and is certainly going to get Commonwealth gold. I can't see anyone beating him in the 200m breaststroke. He will have less pressure than in London. I think 2014 is fantastically positive for him. I don't think he will feel that much pressure because he knows he is going to win that 200. If I was a betting man, I'd put a few bob on it.

"It should be fairly easy for him, mentally. Then one comes to 2016, and whether he has the mental strength to [win at the Olympic Games]. The Commonwealths are not easy: fantastic competition, but they are not the Olympic Games."

One problem Jamieson will not experience is that which confronted Wilkie 40 years ago. "I had to plead to get away. My coach did not understand: 'Why do you want to go all that way to swim in this two-bit competition?' I went home to Aberdeen to see my parents and then jetted off to Christchurch via Dubai and Sydney. The trip took about 48 hours and I arrived absolutely knackered.

"Then, John Hogg, the coach, stuck me in the 400m individual medley which I'd never swum in my life. It totally buggered me and I lost the 100m breaststroke. I got silver because I just wasn't mentally prepared. Thank goodness, two days later, I'd managed to get over the jetlag and won the 200m and then the 200m individual medley.

"Two golds and a silver was okay, but I remember it mostly for the hassle getting there and my coach not being too enamoured about me leaving training to go halfway across the world. To him it was a non-event. The Americans are rather insular."

Wilkie's affection for Sri Lanka and Aberdeen endure. After the catastrophic tsunami, he supported a charity through Colombo Swimming Club, teaching Muslim women to swim. So many died needlessly that it left him distressed.

"But everything in Sri Lanka, once the politicians have had their, sort of, er, input . . . well, sadly that charity has not really progressed as one would have thought it would.

"It taught a few people to swim, but sadly it isn't really operational. There are charities I am involved with, but that particular one is no longer on the go."

His parents, now gone, retired to Aberdeen. "My sister is still there and my niece teaches there. I still support Aberdeen and have fond memories. Aberdeen is always going to have a place in my heart."