Entries for this year's Barrathon filled up in a record six minutes, but those hoping to take part in the half marathon can still be placed on a waiting list. The race will be held on Saturday 29 June at 7:30pm on the Isle of Barra in the Outer Hebrides.
The race is a clockwise circuit of the island, following an undulating course, the lowest point being near sea level and the highest point being just under 350 ft. The route starts and finishes in Castle Bay and in addition to the undulations it offers some respite with a mile-long descent.
Race organisers warn that it isn't for the faint of heart: "Your legs will turn to iron and every sinew of your body will hurt. Eventually you will arrive at Castlebay School where somebody will ask how you are feeling. Luckily for them you'll be too exhausted to let them know the exact truth."