Is The Dragon's Back the toughest race in the world?

The Olympic party is all but over. Games euphoria is ebbing, the media is reverting to its customary diet of stories that sap your faith in humanity, sponsors and suppliers are counting their winnings; and – Paralympics notwithstanding – thousands of athletes , volunteers and Londoners are contemplating the remainder of 2012 with a gathering sense of anti-climax.

Yet the year's supreme sporting challenge has arguably yet to take place.

Next Sunday, at 7am, in the cold shadow of Conwy Castle on the north coast of Wales, nearly 100 of the world's toughest athletes will assemble on an unmarked starting line for what some claim is the toughest race ever.

The Dragon's Back isn't quite a once-in-a-lifetime event. There was one previous running, in 1992, which passed quickly into folklore – or, at least, into that obscure appendix of folklore in which the legends of extreme endurance sports are chronicled.

The parameters were simple: a 200-mile run along the mountainous spine of Wales, from the top of the principality to the bottom, broken into five-day-long sections, with 45,000ft of ascent and descent – on terrain so rough that much of it was barely suitable for scrambling, let alone running – with no defined route apart from a few dozen map references indicating checkpoints.

That makes it sound easier than it was. A 200-mile route can feel like a 400-mile route if it has enough ups and downs in it. And it is, in any case, only a 200-mile route if you never deviate from it. In practice, it was all too easy to add f dozens of unnecessary miles through unintended detours. The mountains were – are – mostly trackless, and even on clear days, great skill is required to pick the best way from A to B. But those particular days were far from clear, and even the best orienteers found the route-finding as much of a challenge as the endurance.

Initially conceived as a low-key challenge for locals, the 1992 Dragon's Back race somehow snowballed into an international event. A sponsor was found; there was interest from foreign television; and the organiser, a long-distance runner and retired paratrooper called Ian Waddell, found himself dealing with one of the hardiest fields of athletes ever to compete on British soil.

Celebrated ultra-runners from America, Scandinavia and Europe lined up alongside the biggest names in British long-distance fell-running, as well as three teams of paratroopers. For safety reasons, they ran in pairs, although Sweden's Rune Larsson, three-times winner of the 153-mile Spartathlon in Greece, secured special permission to run alone. (He didn't want to be slowed down.)

No one who has not tried running all day on steep, rocky, slippery, fog-bound British mountains can really understand quite how debilitating such an experience can be: the deep, soul-consuming exhaustion; the bruising; the bone-aching damp and cold; the disorientation; the occasional fear; and, not least, the sheer extra effort required both for going up a steep, uneven slope and for coming down. And no one who has not tried at least one multi-day, ultra-endurance event can really appreciate the depths of resolve required to force stiff limbs and battered joints back into basic motion and, then, into vigorous action, at dawn after dawn after dawn.

But the 55 runners who contested the Dragon's Back in 1992 either knew or, if they didn't, found out soon enough. Each day was an epic test of willpower and resilience in its own right. And each day was harder than the last.

For most contestants, it became a question of survival rather than winning the race, as they realised quite how hostile an environment they had been lured into. Rune Larsson described to The Independent's Rob Howard how, early on, he became trapped on a rockface, with no idea how to get off. "I was lost in the mist in a strange country and felt very alone… frightened and thinking of my seven-month-old son."

One by one, contestants admitted defeat. The first retirements came as early as day two. Only half the field made it to the end of the fifth day.

Oh yes, and one other thing: one half of the winning pair was a woman.

But more of that later. The main thing to note is simply that, when those involved looked back on the five-day ordeal, the collective feeling of 'never again' was so overwhelming that, by tacit common consent, it was not repeated.

Until now. In 2010, Shane Ohly, a marketing consultant and mountain-running nut from Cornwall who had read about the 1992 race, began to wonder if the recent boom in adventure sports might have created a new generation of runners worthy of testing themselves against such a challenge. As soon as he wondered, "a light bulb went on, and I decided to try and organise the event for myself".

Why? "Because I like doing things that are hard. I like trying to rise to challenges. And I wanted to organise something for people like myself."

Nearly two years later, his idle fantasy is about to turn into painful reality. Ninety-three contestants – selected after careful vetting from 300 applicants – will set out on 'Dragon II' in eight days' time. As well as some of the biggest names in British fell-running – Steve Birkinshaw, Mark Palmer, Nicky Spinks – there are runners from Canada, the US, Australia, New Zealand, Scandinavia, France, Spain, Germany, South Africa and Belgium. Ohly hopes that at least some will be tough enough to be still running when they reach the final steep, uphill, rocky climb to the finish at Carreg Cennen castle, at the south-west tip of the Brecon Beacons.

The route will follow the same broad lines as in 1992, but the details, necessarily, will be different. Guidelines for competitors give a helpful list of nine different Ordnance Survey maps through which (somewhere) the course will pass. Map references for the actual checkpoints will not be released until 7am on each day of the race.

"I've included a lot more checkpoints than last time," says Ohly. "And more peaks." The advent of digital timing devices makes it easier to establish reliable unmanned checkpoints. "So there are more fixed points – but also more route choice."

This should offset any notional advantage conferred by the race having been run before. In purely physical terms, says Ohly, "I reckon it's about 5 per cent harder that the original race."

Organising it has been a challenge of Olympian proportions. Not only has Ohly had to familiarise himself with the entire route himself, repeatedly and on foot. He has also had to organise overnight campsites, catering, insurance, permissions (you can't run 200 miles in modern Britain, even in mountainous Wales, without crossing all sorts of patches of private or restricted-access land) and any number of other time-consuming administrative details.

Twenty years ago, Ian Waddell persuaded his old colleagues in the Parachute Regiment that it would be an excellent training opportunity for them if they were to take on the logistical responsibilities. And so, rather like the uniformed soldiers who helped the Olympics to run so happily in London, scores of paras manned the checkpoints and campsites and back-up transport and generally made sure that nothing went too badly wrong.

Shane Ohly has to rely on his own 150-strong team of volunteers – another Olympic echo. Indeed, at least one of these is coming fresh from being a London 2012 Games Maker. "Straight afterwards, he's going back to help at the Paralympics," says Ohly.

Simply arranging for all 150 of these to be in the right place at the right time, doing the right thing, is a fairly mountainous responsibility. But Waddell and others have been generous with advice, and the aura of the Dragon's Back is such that there is no shortage of people who consider it an honour to be involved.

Things may not run with quite the same military efficiency as in 1992 or, for that matter, as the Olympics. But there should be a comparable sense of communal endeavour. And Ohly is confident that he has at least got right the "most important thing" – the food for the overnight stops. "I asked catering companies to prepare quotes on the basis of doubling their usual quantities per person. And then I told them to add 30 per cent."f

Meanwhile, those who care about such things are focusing not on overnight comforts, but on the race itself: who will win it, who will complete it, and, most of all, how it will compare with the legendary Dragon's Back of 1992.

Speculation on the first two questions will mean little to non-specialists. It is wonderful, after all the spine-tingling feats we have already witnessed in recent weeks, to know that this glorious sporting summer is not yet over, and that athletes of the calibre of Steve Birkinshaw and Mark Palmer are about to take on the biggest challenge of their lives. Birkinshaw is seven-times winner of the Original Mountain Marathon; Palmer is one of only two men in history to complete the Lake District's notorious 42-peak Bob Graham Round in under 15 hours. But if you don't know what such phrases mean, you may struggle to get excited by this information.

Helene Diamantides, however, is a different matter. A 48-year-old physiotherapist from Harrogate, she is as much part of the Dragon's Back legend as the mountains themselves.

Twenty years ago, she was little known even among fell-runners. She had knocked off a few records for fastest woman to do this and that. But she was relatively new to the scene; and, in any case, male runners tended not to take women very seriously back then. Indeed, it wasn't long since women had been barred from entering many fell races, because they were considered too delicate.

But Helene, a quietly-spoken woman of Greek descent who could not by any stretch of the imagination be described as unfeminine, had a gift for endurance that most macho men could only fantasise about.

Running with Martin Stone, a famous long-distance fell runner and orienteer, she soaked up the punishments of the Welsh mountains with seemingly effortless resilience. While champion ultra-runners and hardened soldiers floundered in their wake, the pair seemed positively at ease in the wilderness, navigating with such confidence in the mist that occasionally they would deliberately head off in the wrong direction, luring those who were trying to tag along before suddenly sprinting off.

There were low points. On the fourth day, on the remorseless tussock grass of the Elan Valley, Diamantides briefly found herself unable to walk. "I keeled over into a bog and didn't get up again. Martin force-fed me chocolate, took my rucksack and spoke very roughly to me." It worked, and she was able to force herself onwards.

On the fifth day, the hardest of all, something similar happened to Stone. So Diamantides carried his backpack for him, as well as her own, for much of the day. This helping hand made all the difference. Stone's legs revived themselves, more or less. Eventually, half-delirious with exhaustion, they staggered tearfully over the finishing line, the first and only victors in a race that had seen a couple of dozen of the world's hardiest men give up in despair. The pair's nearest rivals were half-an-hour behind. The fastest team of paras was 13 hours behind.

It was a remarkable achievement. It was also resoundingly impressive as a demolition of the facile contention that women are the weaker sex. Women have been inching closer to men in many athletic disciplines in recent decades, but progress has been slow. Diamantides's achievement suggested that, in endurance events at least, women could ultimately be even tougher than men.

Twenty years later, Diamantides is a busy (and doting) mother of two small girls, struggling to find time to exercise at all in between the demands of work and parenthood. She is, however, still running when she can, despite assorted injuries, and still in love with wild places and implausible challenges. When word of the rerun of the Dragon's Back reached her, it took only a moderate amount of agonising, and an encouraging prod from her husband, before she succumbed. (Stone, by contrast, is no longer running, although he will be in Wales to give moral support.)

"It seemed a good idea at the time," she says, in tones that suggest that it doesn't seem quite so good now. It hasn't been easy to put in the requisite training: not because of being older, but because it isn't possible to spend that much time away from a young family. "In the old days, I did what training I chose. Now I do what I can. But I think I'm a better balanced, less obsessive human being than I was 20 years ago."

Could that be an advantage, when the going gets tough? "No. I think you're better off being horribly obsessed."

Looking back, she says she can barely remember the agonies of 1992. This, I think, is nature's way of keeping such sports going. If people could remember the pain, they'd stay at home.

No one expects Diamantides to win this time, but there is huge interest in how she fares. In 1992, she showed what a young, single, highly-focused woman in her athletic prime could achieve through self-belief and inner grit. If she completes the course this time, it will say something about what a different kind of woman can achieve: the busy working mother who recognises that some things in life matter more than the results of races – but who none the less retains her grit and self-belief and refuses to allow stereotypes to limit her dreams.

"I'm really hoping that I'll be able to get to the finish," she says. "I'm hoping I may enjoy it, too. But neither is a foregone conclusion."

I hope she succeeds. She may not get enough publicity to inspire a generation. But she might inspire a gender.

Richard Askwith is the author of 'Feet in the Clouds: A Tale of Fell-running and Obsession' (Aurum, £8.99)