Pipped to the post: What happens to famous athletes who just miss a place on the podium?

It is impossible to imagine the emotions and memories that will be running through the mind of Paula Radcliffe on Sunday, 5 August. At 11 o'clock that morning, the crack of a pistol will signal the start of the women's Olympic marathon.

Radcliffe is among the most decorated athletes due to take part in the race, but for her, the Olympic Rings have always been barbed. She came fifth in the 5,000m in 1996 in Atlanta, and fourth in the 10,000m in 2000 in Sydney. Four years later, the accumulated misery she has endured on the greatest sporting stage was concentrated in the sweat and tears that splattered a pavement in Athens.

Radcliffe arrived in the Greek capital at the height of her career. She had broken the world record in London the previous year, and would become world champion in 2005. But in the heat of Athens, and under the huge weight of expectation at home, Radcliffe buckled. With four miles to go, she watched an Ethiopian runner ease past her into bronze medal position. Her dreams of a place on the Olympic podium dashed yet again, she slumped by the side of the road, broken and inconsolable. As she had said in Sydney, "No one remembers who came fourth".

Medals will be awarded to athletes in 60 events in 46 sports at the 2012 Olympic and Paralympic Games in London. For every winner, there will be a loser who will suffer the peculiar torment that comes with just missing out. Fractions of seconds, centimetres or grams can be the difference between victory and crushing disappointment. For some, these tiny measures can also separate glory and anonymity in the eyes of a public for whom medals are worth more than their weight in gold, silver or bronze.

Jon Brown is perhaps the best British athlete you've never heard of. He, too, came fourth in the marathon at Sydney. After running for two hours and 11 minutes, he missed out on a medal by just seven seconds. Brown felt stronger still at Athens four years later, a week after Radcliffe's agony. "My training had gone exceptionally well and I believed a medal was possible," he says from his home in Victoria in western Canada. "I ran better than in Sydney and had gone into the race fully targeting a medal."

But when Brown, now aged 41, entered the final stage, inside the cauldron of the Panathinaikos Stadium, he was more than a minute behind the eventual winner, Stefano Baldini. Worse still, he crossed the line 15 seconds behind the man who finished third. Again, there would be no medal, no moment on the podium, no smiling post-race photographs in the papers. "It was very difficult," he recalls. "Within a few minutes of crossing the line I was sitting down in tears. It was the realisation that there would be no more opportunities to win an Olympic medal."

Margins in sport have become agonisingly fine with the advance of technology. On the track, computerised timing and photo finishes can separate athletes by thousandths of seconds. "We used to be much more relaxed about dead heats," says David Wallechinsky, a commentator for the American NBC network and renowned Olympic historian. "You come really close today and wonder, what if I'd let my fingernails grow?"

As the difference between victory and defeat shrinks, so the pressure to win medals grows, reaching almost insufferable levels for the 550 British athletes competing on home soil this year. Earlier this month, UK Sport, the body that distributes millions in public and National Lottery money, threatened to stop sending cheques to several sports unless it could be convinced of their podium prospects. All eyes will be on the medals table in London. There, at least, UK Sport has said it will be satisfied with fourth position. But for athletes who want a career, fourth can be the cruellest place.

Sometimes, however, sport can offer salvation. Mary Peters came fourth in the pentathlon in 1964, and ninth four years later, before winning gold in Munich in 1972. Twenty years earlier, at Helsinki, Sir Roger Bannister was a relatively little-known student and runner. He was favourite, however, to win gold in the 1,500m. But with half a brain on his studies (he would go on to become a distinguished neurologist) his "just enough" training strategy backfired when the organisers introduced semi-finals. The extra race left Bannister with nothing left for the final sprint, and he fell back, eventually crossing the line in – yes – fourth place.

"It seemed at the time the worst moment in my career," the 83-year-old Bannister says from his home in Oxford. "I had managed to win most of the things I had wanted to win, so I was struck with the disappointment of not having done myself justice."

Bannister had planned to retire immediately after Helsinki, but the shock of loss inspired him to keep going for two more years. He trained harder. The rest, of course, is sporting legend. In 1954, on a track in Oxford, he became the first person to run a mile in less than four minutes. After winning Commonwealth and European golds in the 1,500m in the same year, he retired from running aged 25. "It would obviously be very nice to have an Olympic medal, but you have to be philosophical about these things," he says. "And had I won the gold, I would have retired, and the four-minute mile would not have been mine."

Muriel Hearnshaw had to wait much longer for some sort of compensation. She was 17 when she travelled to London from her home in Yorkshire to compete in the women's sprint relay at the 1948 Olympics. The British team finished fourth, behind a winning Dutch quartet that included the female "athlete of the century", Fanny Blankers-Koen. "I was disappointed because we'd got the third fastest time in our heats," she says. "Of course, you finish fourth and always wonder in your mind if you've not run as well as you should have done." Injury prevented Hearnshaw, née Pletts, from competing in 1952, and she moved on to a quiet career as a secretary.

Later, Hearnshaw's daughter, Susan, showed talent as an athlete. Muriel, who's now 80, contributed to her coaching and, at the 1984 Olympics in Los Angeles, she and her husband watched their daughter compete in the long jump. After a close contest, Susan came third, missing out on silver by the width of a shoelace, but winning the bronze medal her mother had failed to grasp 36 years earlier. "She wasn't happy, but we thought she'd done all right," Muriel says. "It was wonderful for me to see."

Jon Brown will have to hope for vicarious pleasure in London. He did not run in Beijing in 2008 but will be at the Games this year, as the coach of the Canadian men's triathlon team. A withdrawal of lottery funding after his second Olympic disappointment in part compelled the athlete to switch his allegiances to Canada (he has dual nationality). He regrets the obsession of the media and funding authorities with medals. "What's undervalued is the process of becoming an Olympic athlete and how to bring these qualities to the wider population," he says. "Funding should have a broader success criteria than just how many medals a sport wins."

For some athletes, a string of fourth-place finishes can hang like an albatross around the neck where a medal might otherwise have shone. Paul Dickenson, the veteran BBC athletics commentator, remembers the contrasting fortunes of his colleague, Brendan Foster, and the less well-remembered British runner, Anthony Simmons. Foster won a bronze medal in the 10,000m at Montreal in 1976, one place ahead of Simmons. "I remember Tony saying years later that just missing out was one of the worst experiences of his life," Dickenson says. "It was the race that broke him – he was never that good on the track again."

Which brings us back to The Mall, where Radcliffe will wait for the start of the marathon. She picked herself up after Athens but, unfit in Beijing in 2008, she could only finish 23rd. London will be her fifth attempt to win an Olympic medal. Dickenson wonders how she will cope. "Psychologically, when you get to Paula's stage of superiority, the Olympics is all that matters. She really has only got one more chance and you think, is she destined never to get the big one?"

Expectations, at least, are lower this time. Radcliffe is 38 and has suffered with injury. Fourth place would be considered a good result if she could achieve it. But no athlete aims to lose. "The thing is, I'm big on perseverance," she told The Independent in April. "I believe that if you keep trying and trying and trying, your odds have got to improve rather than if you give up and say, 'Oh the Olympics just weren't lucky for me'." She added: "I'm in it to win it. I wouldn't be competing if I didn't think I could."