This Saturday 2400 youngsters aged between 14 and 19 will take part in the annual Ten Tors challenge on Dartmoor. This Army-run event is one of Britain's biggest adventure challenges for young people.

The teenagers will hike unaided over 35, 45 or 55 miles of some of the toughest terrain and the highest ground in Southern England. It is a feat they must complete as a team and without any help from adults.

The majority of the teams are from schools and youth groups from Bristol, Cornwall, Devon, Dorset, Gloucestershire, Somerset and Wiltshire. As usual, scores of scout groups, sports and ramblers teams and Armed Forces cadet units are taking part too.

For many youngsters it was a challenge just to be selected for their team, say organisers, such is the competition to take part in the event.

Central to the spirit and ethos of the Ten Tors Challenge is that teams who take part remain entirely self-sufficient, camping out overnight on the moor and carrying all their food, water, bedding, tents and other essentials.

All participants will have been in training for at least four months or more to make sure they're fit enough to complete the course. It is a rite of passage which has played a formative role in the lives of more than a quarter of a million people from across region over the last half Century.

Immediately after the start of Ten Tors, nearly 300 youngsters with special physical or educational needs - many in wheelchairs - will start the Jubilee Challenge, competing routes up to 15 miles. The youngsters can enter either as a team or as individuals, each one accompanied by an Officer Cadet from Exeter University Officer Training Corps.

'For more than 50 years, the annual Ten Tors Challenge has shaped the values, attitudes and fitness of thousands of young people' said Brigadier Piers Hankinson MBE, Director of Ten Tors and Commander of 43 (Wessex) Brigade.

'It literally changes lives for the better. Over those years clothing, equipment and regulations will have changed, but the underlying challenge of walking unaided over the forbidding Dartmoor terrain remains as demanding today as it has ever been.'

'To complete Ten Tors and the Jubilee Challenge takes considerable commitment and determination, not just from the individuals and teams participating, but also from the adult team managers and group leaders whose selfless commitment and dedication bring the experience and love of the wild to new generations.'

'We will be presenting more Ten Tors Awards again this year to those essential adult volunteers, whose dedicated support has kept the Ten Tors Challenge alive.'

'I remain extremely grateful to the Dartmoor National Park Authority, the emergency services, Dartmoor Rescue Group, Devon Air Ambulance Service and Red Cross and to all the many other voluntary organisations and individuals, too many to mention, for their continued assistance with the safe conduct of the Ten Tors Challenge. Safety remains our primary responsibility.'

'Good luck to the participants and I look forward to meeting you in Okehampton Camp or on Dartmoor.'

One of the most enduring legacies of Ten Tors is a lasting appreciation of the beauty of Dartmoor which is instilled in every young person taking part, say organisers. For some it may be the first time they have spent any length of time walking in the countryside, igniting a lifelong passion.

Team managers are guided to encourage participants to develop a respect for the landscape, cultural heritage and wildlife of Dartmoor, and Ten Tors organisers work closely with the Dartmoor National Park Authority (DNPA) and others to help those taking part to appreciate and understand Dartmoor's special qualities.

Kevin Bishop, DNPA Chief Executive, said:

'Ten Tors and the associated Jubilee Challenge are part of the Dartmoor calendar. They provide a unique opportunity for young people to experience the special qualities of the National Park and, we hope, to develop a passion for the National Park. We are pleased to work in partnership with the Military, Commoners and other agencies to help make the event a success: to minimise the impact on the natural environment, maximise the benefit for the local economy and provide people with an opportunity to learn more about the National Park.'

Since the first Ten Tors in 1960 the weather has always played a part in making it the challenge it is. Luckily this year's forecast looks good. Despite heavy rain in the run up to the event forecasters at the Met Office are predicting clear blue skies for the weekend itself.

Scores of teams have spent the day setting up their tents at Okehampton Camp under persistent drizzle, but this is expected to clear around Midnight leaving the nearly 3000 youngsters taking part in the events, and several thousand spectators, with a weekend of sunshine to look forward to.

'The latest forecast is for high pressure to dominate the weather over the weekend' said Met Office Forecaster Helen Chivers. 'This will bring very pleasant sunny conditions for those taking part in the Ten Tors and the Jubilee Challenge with daytime temperatures of around 10 degrees. Although it's not going to be hot by day, the sun is strong at this time of year, so sun cream will be a must. But the clear skies will mean it will be a little chilly at night.' <.