A sunsrise set-off for runners at Conwy Castle. Photo: Rob Howard

One of the world’s most gruelling mountain races got underway today, with 91 competitors from 14 different countries starting to the rousing sound of a Welsh male voice choir.

The runners, some from as far away as Hong Kong, Australia and New Zealand, set off from Conwy Castle at 7am to tackle the 320km (199-mile) Dragon’s Back Race, which also involves more than 15,000m of ascent.

The route runs from north Wales down the backbone of the nation to finish in five days’ time at Carreg Cennen Castle in the Brecon Beacons.

The runners only discover their route for each day on that morning, having to plot a course that allows them to reach each and every checkpoint that the organisers have placed on the mountain summits.

The race has only been held once before, in 1992, when just half of the competitors finished. Back then, one winner was Helene Whitaker, who has returned to tackle the Dragon again.

She is joined by some of the world’s best adventure racers, including fellow British ultrarunner Steve Birkinshaw, one of this year’s leading contenders. There is no cash prize for this event, just a trophy and the glory.

Organiser Shane Ohly said: “The magic of the Dragon’s Back Race is, I think, that it offers competitors a phenomenal journey in the mountains through places that very few people go.

“Add to that the incredible physical and mental challenges, which really appeal to the most dedicated adventure racers, and you have something very compelling, exciting and almost mystical.”

The Maelgwn Male Voice Choir provided the vocal send-off for runners at the start.