 Halfway up the mountain, the boy began to shake uncontrollably. Frozen to the spot, he started to stutter. He was, he said, terrified of heights. The 17-year-old and his classmates from Welbeck Defence Sixth Form College were climbing Tryfan, in Snowdonia, a mountain with exposed ridges and daunting peaks.  "He was very, very uncomfortable - nervous and shaky," recalls Flight Lieutenant Trudy askew, the member of staff responsible for training the group. "But he didn't back out, and ultimately he made it to the top. "That's what we facilitate - that sense of achievement that pushes people on."  Welbeck, near Loughborough in Leicestershire, offers teenagers from all backgrounds a science- and technology-based curriculum designed to give them a head start in training for a career as an officer within the armed services, or as an engineer within the Ministry of Defence Civil Service. Most of its students are MoD-funded but a small number pay the ?18,000 annual fees.  at Welbeck, an academic education is necessarily combined with outdoor activities to develop the levels of physical and mental strength pupils will require for a military career. But more and more independent schools are recognising the role that outdoor education plays in ensuring their students leave school not only healthy and active but also with skills that extend beyond coursework and exams.  at abbotsholme, a private boarding and day school in Staffordshire, where boarding fees peak at ?9,225 per term, pupils have access to an on-site equestrian centre as well as a working farm. They bale hay, muck out stables and help with the births of cows, sheep and horses.  "I've seen the roughest, toughest rugby players in tears when they're holding a newborn lamb," says headmaster Steve Fairclough. "It's not only about learning respect and humility, it's about knowing how to care for a living thing. That helps them deal with people in a more humane way."  Staff at Welbeck also believe that being outdoors helps to develop strength of character. School-based workouts are complemented by "adventurous training" in Snowdonia, and trips to the Scottish mountains in winter. and pupils regularly suggest outdoor challenges - a three-mile outdoor swim or a 45-mile mountain trek, for instance - which teachers help them achieve.  "By overcoming challenging situations, your confidence grows," says Flt-Lt askew. "Later on, when faced with a real-life situation, you are hopefully able to find the inner strength to deal with it."  aCS Cobham International School in Surrey, which takes children aged from two to 18 (and where day fees cost up to ?20,820 per year), places a similar value on outdoor activities.  Pupils engage in outdoor learning opportunities in a customised woodland clearing. By the age of nine they have learnt to build a shelter, light a fire without matches and cook their own meals. The risks, uncertainties and potential surprises can provide an invaluable grounding for life beyond the school gates.  "They're not afraid," says Lacy Chapman, principal of the Lower School. "We're teaching them to be in control of their environment."  From the age of two, her pupils are introduced to aquatic life at the school pond and help tend an on-site vegetable garden. "You can't make an eight-year-old take on global warming as an issue," says Chapman. "But you can encourage them to take responsibility for their own garden. One hopes a feeling of achievement, however small, will instil a wider sense of responsibility."  This is a common refrain among teachers: it is one thing to read about environmental awareness in textbooks, quite another to understand it through practical experience.  at abbotsholme, the heavy frost last winter killed several trees. Subsequently, pupils were drafted in to chop up the wood. "First they understand why the trees died. Then they begin to realise what the seasons mean and why they're important," says headmaster Steve Fairclough.  at Dolphin School, a preparatory in Berkshire that charges up to ?3,730 per term, outdoor lessons are deemed so worthwhile that they constitute an intrinsic part of the curriculum.  From Reception onwards, Dolphin pupils are taken on a residential field trip every year. Each is deliberately tied to a topic within the curriculum - so, for instance, younger pupils might be taken on a visit to East Sussex for two nights to enhance history lessons about the Battle of Hastings, while Year-4 pupils will study coastal erosion in Dorset, as well as complementing their English lessons with a visit to Thomas Hardy's house.  "The classroom is a bit of a sterile environment," says deputy head Christopher Leakey. "You're trying to learn about something that didn't take place there, which relies on a dynamic teacher. But seeing first-hand how a river can erode its way through the land, or how castles are built, does make a difference. Taking children to see what's going on in the real world makes it stick."  Such excursions also ensure that a child's knowledge is not defined by individual subjects on a timetable. a trip to a quarry, for example, will not only highlight geological formations but also provide an opportunity for discussion during a visit to a castle built from local stone. Inevitably, this cross-curricular perspective and flexible thinking is appealing to universities.  Other types of outdoor work can provide similar breadth of perspective, with commensurate levels of benefit. abbotsholme pupils, for example, commit to looking after the school's cattle for an extended period of time. "The difference between this activity and a maths lesson is the recognition that if they don't turn up something living will suffer," says Fairclough. "That enforces repetition and gets kids used to routine. The opportunity to learn [basic life] skills are often lost today."  Jon Gray, head of the ?3,990-a-term Hornsby House School, takes this one step further, believing that outdoor activities can be character building. at his south London prep, all the year groups take turns at clearing the playground of litter. and, during a final-year field trip, 11-year-olds conduct a littersweep of a Scottish beach.  "If you're the type of person who leaves an environment in better shape than you found it, you'll live a happier life," says Gray. "and you'll also be an easier person to get on with. In the vast majority of jobs, the ability to get on with people plays a huge part in your success."  Flt-Lt askew agrees. When her 17-year-old mountaineer  