Lessing is clear favourite for that debutant step on to the podium in Sydney, the hot bed of the newest and arguably most physically taxing of Olympic sports. No matter that he has never lived in Britain and has an accent closer to Cape Town than Clapham. Compared to Lessing, those other born-again Brits Greg Rusedski and Lennox Lewis may seem like Cor Blimey cockneys, but if he strikes Olympic gold you can be sure we will claim him as our own.
And why not? Lessing holds two passports but he says his British roots are strong. His mother and maternal grandparents were English born and both parents - his father is South African - now live in Scotland.
"I was always going to compete internationally as a Briton," he said. "I really had no other option. I was brought up in South Africa at a time when it was impossible to take part in sport internationally as a South African because of the political situation. It was not so much a matter of expediency but of necessity. I certainly have no problem with being part of the British set-up in triathlon because, as a nation, we probably have the strongest squad in the world."
Even so, Lessing remains largely unrecognised in this country, despite his superman status within the sport and a physique and personality that would make him a natural for any TV sports celebrity panel. He has never yet been able to accept an invitation, as one of Britain's few world champions, to the BBC Sports Review of the Year mainly because his swim-cycle-run event demands the sun on his back for most of the year. He has lived in France for 10 years, and has a house in Provence which he shares with his American wife, Lisa, a former top US triathlete.
His other stamping grounds are South Africa and California, both climatically conducive to bringing out the best for those who train for a discipline which takes around one hour 45 minutes of non-stop athleticism, beginning with a 1,500m swim in a river or lake, often against strong currents, a 40km bike race and finally a 10km road run.
Unlike its bigger brother, the five-sports modern pentathlon, which lasts a whole day, there is no time to catch your breath and hardly time for the lads to get their kit off - and on again - for the next event.
Lessing points out that spending most of your time abroad is the rule rather than the exception for top British triathletes. Andrew Johns, now his closest rival both domestically and internationally, and the former world No 1 Spencer Smith, both live and train in California. Johns, 25, though Peterborough-born, lived in Australia as a youngster and only switched his allegiance to Britain a couple of years ago. He holds the top world ranking based on points won in World Cup contests this year. Smith, 26, became the first man to retain the world title in 1994, having wrested it from Lessing two years before. Between them they have helped Britain secure more world titles at senior and junior level than any other nation in the last decade.
Last week Lessing made a rare trip across the Channel to spend a few days at Bath's Sports University in preparation for the world championships and the subsequent London championships, where he is aiming for his third successive victory in the Docklands event just a week later. Bath is the base for Britain's new performance director, Greg Millet, a former top French triathlete. Never mind Dean Macey, according to Millet, Lessing is at present Britain's finest all-round athlete.
"The triathlon requires you to use every muscle in the body as well as the brain. It is the most demanding sport of them all," Millet said. "You have to out-think your opponent as well as out-swim, out-ride and outrun them. At the end you are physically and emotionally drained." You certainly need to be a superman to survive or at least an Iron Man, the nine-hour endurance test from which the triathlon is derived. It began in California 25 years ago and is now one of he world's fastest growing pursuits, not least in Britain where some 4,000 will contest the London event, making it second only to Chicago as the world's biggest triathlon.
Through prize money, sponsorship and now Lottery funding Britain's elite can live comfortably and compete on level terms with the sun-ripened hunks from Australia and New Zealand. Britain has Olympic medal chances in the women's event, too, with four of the world's top 10, led by 30-year- old Sian Brice, but it is to Lessing and Johns that the country is really looking for a spot of inaugural gold prospecting in Sydney where, in an Australian spring, the winds will be cool but the home support boiling.
Britain's third man, Smith, sadly has other matters on his mind at the moment. He is trying to fight off a drugs slur having tested positive for our old friend nandrolone after competing in an Iron Man event in Hawaii last summer. He was later cleared by the British Triathlon Association after successfully pleading that rules were not properly followed by the Americans. However, the Vancouver-based International Triathlon Union ordered a rehearing and Smith has taken the matter to court, claiming they have no right to interfere in the domestic decision.
So the newest sport in the Olympics is bedevilled by one of the oldest controversies. For his part, Lessing elects not to become embroiled in the matter, but hopes it will be cleared up satisfactorily so that triathlon can take a higher profile in the British sporting consciousness. "We are fighting a conservative attitude in Britain," he said. "It hasn't helped that we have had this business and there is a misunderstanding that you have to take drugs to be successful. That simply isn't so. Also people look upon it as a crazy sport, only for supermen, but lots of ordinary athletes take part and get great enjoyment from it.
"What we are seeking is a respect for the sport at least on a par with some others which may not be quite as successful." Lessing argues that triathletes are not simply a circus of strongmen, performing mind- boggling feats of human endurance three times daily. "We are certainly not freaks, just athletes who are dedicated to getting the best out of their bodies." That, of course, is what sport is supposed to be all about. But to be a triathlete you surely have to be something extraordinary.
With his wrap-around sunglasses, tanned features and muscle-sculpted tapering torso Lessing, at 1.95m (he admits he is not quite British enough to talk in feet and inches) and 75kg looks the perfect specimen for a sport designed for the aerodynamic age.
They say the triathlon is the ultimate sport and one which will catch the millennium bug. If a Briton, even a non-residential one, can beat the Aussies at their own game on 17 September next year it will certainly become contagious. Lessing quietly relishes the challenge. "The sport is growing so rapidly that there may well be strong contenders we haven't heard of yet. But, looking at it realistically, I know I have a chance. To stand on the Olympic rostrum has always been my goal, my vision."
To be the first Olympic champion of the 2000 Games may require gold medal performances in three sports but, as Lessing knows, the most important ingredient is a single mind.