The mass start of the Ten Tors. Photo: Adrian Harlen/MoD

The Army and hundreds of young competitors are gearing up for an annual test of stamina and navigation on Dartmoor next weekend.

The Ten Tors gets underway next Saturday at 7am, with 2,400 teenagers expected to tackle the course over 35, 45 or 55 miles.

The challenge crosses some of some of the toughest terrain and highest peaks in southern England and competitors must rely on their navigational skills and carry all their food, water, bedding, tents and other essentials as they go.

The 54th running of the event starts at Okehampton Camp and a shorter course, the Jubilee Challenge, is undertaken by youngsters with physical or educational needs.

Most of the teams in the Ten Tors are from schools and youth groups from Bristol, Cornwall, Devon, Dorset, Gloucestershire, Somerset and Wiltshire, along with scores of Scout groups, sports and ramblers teams and armed forces cadet units.

The Army said the challenge will be even harder this year. For the first time in more than 30 years the Ten Tors has new routes aimed at improving resilience and enhancing safety of the event.

Brigadier Piers Hankinson, director of Ten Tors and commander of 43 (Wessex) Brigade said: “The policy committee and I have implemented changes to reduce the need for participants to cross certain water obstacles and to walk along busy public roads.

“We have also reduced the dependency of the event on helicopters – for obvious weather implications – and so the locations of safety control points have moved closer to road-heads rather than on top of the Tors; checkpoints remain on the Tors.

“I believe these changes will not compromise the original aims of the event: to develop teamwork and practice navigation. If anything the challenge will be more demanding, with the experience and appreciation of a high moorland location and the associated weather conditions of a challenging environment.”

Kevin Bishop, chief executive of Dartmoor National Park Authority said: “Dartmoor is a special place and Ten Tors is a special event.

“We wish those participating all the best and sincerely hope that the thousands who have been involved in training and the actual event will have developed a passion for the national park and help us to sustain its special qualities for future generations to enjoy.”

The Ten Tors’ founder Lieutenant Colonel Lionel ‘Greg’ Gregory died earlier this year. An Army spokesperson said: “His legacy is that that Ten Tors has stood the test of time and while wool jumpers have been replaced by Gore-Tex jackets it is considered by many the premier youth development expedition in Britain.”

The Ten Tors and Jubilee Challenge take place on Sarturday 10 May.