IT has been dubbed the toughest foot race on earth and is the running event that coined the term ultramarathon.

Competitors taking part in the Marathon des Sables run a total of 251km - the equivalent of more than five marathons - across the Sahara Desert in just six days.

Two instructors from the Army Foundation College in Harrogate have taken up the challenge.

Major Al Grant and Captain Tristan Burwell, both 30, are part of a four-man team that will be heading out to southern Morocco in April for the ultimate test of their endurance in aid of a forces charity.

To prepare themselves for one of the most hostile environments on the planet, where daytime temperatures exceed 100F (50C) and night-time temperatures can plunge to zero, they have been training in the North Yorkshire hills.

Looking forward to the event on 3-14 April, Al said: “We’re feeling strong, but are up against a field of professional ultramarathon runners. Only 1,500 are selected to take part in the competition, so just getting a place is pretty tough.”

“Sir Ranulph Fiennes will be doing it and he will be 71, so we’d better come in before him.”

To donate to ABF The Soldiers’ Charity, go to www.justgiving.com/2015MDSTeam