The trip was beset by problems from the beginning. There were no more than four hours' daylight left in which to cover six difficult miles to the Corrour Bothy at the southern end of the Lairig Ghru. What made this almost impossible was the wind, perhaps the deadliest enemy of anyone covering any distance in the mountains. Anyone trapped here would probably have been all right if the snow had been hard, but over that weekend the snow was powdery, making it impossible to make a shelter or dig a proper hole. The snow, with the help of the biting wind, blew into equipment and sleeping material, which then lost its insulation properties, setting off a cold-wet

spiral that was difficult to overcome. For six children stranded on the Cairn Gorm, amid the worst blizzard to hit the mountains for years, this was to prove fatal.

On Friday, November 19, 1971, 14 boys and girls from Ainslie Park School in Edinburgh, left the city for what was to be an adventure in one of Scotland's toughest wildernesses; something to talk up in class for weeks to come. Leading the group were Catherine Davidson, a student of physical education, Ben Beattie, her boyfriend and chief permanent instructor in outdoor

education at Ainslie Park, and Sheelagh Sunderland, who had no experience in the Cairngorms and was just starting a three-week voluntary stint as an instructress at Edinburgh Education Authority's outdoor centre at

Lagganlia, Kincraig. During the trip, planned as a navigational exercise, the children, aged between 14 and 18, would be divided into groups of two (one more advanced than the other), and would learn to use maps and compasses. On Saturday morning, they left a route plan with the principal of Lagganlia, which included a bad weather alternative involving both parties cutting short their expedition at Curran Bothy.

The original route planned for Davidson and her group involved leaving Coire Cas car park at 11am and climbing to the 4,084ft Cairn Gorm summit in one-and-a-half hours, and going from there to Lochan Buidhe in two hours, before

rising 500ft to Ben Macdhui in approximately one-and-a-quarter hours. Then they would descend to Tailor's Burn in an hour and go through the Lairig Ghru to finish at Corrour Bothy in a further half-hour. The total journey would take six-and-a-quarter hours, ending at Corrour at 5.15pm.

Before leaving Lagganlia at about 11am, Ben

Beattie had given Davidson a weather forecast which was not too bad, but more snow and some wind was expected. The route card indicated that her group should have started from the foot of Cairn Gorm at 11am. She would have had to have left Lagganlia by 10.40am to achieve this. The group ascended Cairn Gorm by chairlift as they realised they were behind schedule.

Davidson's party arrived at the Ptarmigan Restaurant at the top as Beattie's party moved off. She and the others finished lunch at noon and reached the radio station on the summit at 12.30pm. When Davidson and her group left the summit, the children were taking bearings while she checked them. The south-westerly wind grew stronger and it was snowing.

Walking became quite difficult because the snow was drifting and not bearing their weight. About a mile from the top of Cairn Gorm, at Coire an t-Sneachda, she felt her party would have to alter their plans and make for the Curran Bothy around one-and-a-half miles away. At about 4pm she realised they might not find the bothy, which was often snowed over, and decided to try to make shelter near the Feith Buidhe Burn. The worst blizzard of winter was about to descend.

Meanwhile, Beattie, aged 23, realised weather conditions were hampering everyone's progress. By the time he had reached Coire Domhain the increasing wind, deep, soft snow and deteriorating visibility meant he was forced to implement the alternative route, making for Curran Bothy to spend the night. His group reached there about 3.30pm and had to dig out the door to get in.

Davidson did not arrive and Beattie - who had quite extensive climbing and mountaineering experience, although it was mainly confined to Ireland, the Alps, and on the Scottish west coast - thought they had taken another, easier route, with a view to spending the night in St Valery Hut, near Coire Domhain, or Jean's Hut in Coire Chais.

The overnight conditions deteriorated badly and Beattie's group had difficulty opening the door of their bothy because of a bank of snow. The next morning the smallest boy in the party was thrust through the door and managed to dig it out.

Beattie, who had never intended that the expedition to be a test of the children's strength or stamina, was concerned for the other party and had to choose between going back along the route of the previous day to look for them or getting his own party down into the Lairig Ghru as quickly as possible to shelter.

There is always a hazard involved with mountaineering, yet without the risk there is little point in taking part in such activities. What is vital, especially in places like the Cairngorms, is paying attention to the signs. According to experts, the only accurate description of the climate on that plateau is sub-Arctic. Many individuals who have been to the Antarctic and the Himalayas have said that the worst conditions they have experienced have been in the Cairngorms. The Cairngorms are not necessarily dangerous mountains if you start at the bottom, climb to the top, and back down again, but they can become treacherous if you start to cross over them with unknown country and unknown conditions ahead of you.

Teenagers present their own problems, given that they lack the physical and mental strength to withstand extreme rigours. They are more than likely to continue walking, failing to conserve their energy and thus making themselves more susceptible to cold. Many experts believe that groups in this condition can be lulled into a ''death sleep walk'', whereby they get confused, disorientated and, as the body loses more heat, the person cannot make adequate intelligent decisions. In extreme conditions the difference between feeling the agonising effects of cold and actual collapse could be as little as 15 minutes. Death follows shortly after.

After his descent from the Lairig Ghru,

Beattie contacted the principal of the Lagganlia outdoor centre, and learned that Davidson had not returned. Search parties were organised from Glenmore Lodge. It was Sunday. Troops, police and civilian mountain rescue teams were alerted but the search had to be called off when the weather worsened and night fell. More than 50 men took part in the search from dawn the next day and helicopters were brought in.

Sergeant John Duff, who was at the time, leader of the Scottish North-eastern Counties police mountain rescue team, was visiting friends when the telephone rang. He was told that a party of schoolchildren was missing in the Cairngorms and a search was being organised based on Glenmore Lodge in the north. ''It was a terrible night, with heavy snow,'' recalls Duff, who is 69, a tall, and formidably young-looking man for his age, ''and if the party had not reached shelter, their situation was very serious.'' Instructors from Glenmore Lodge, the Scottish Mountain Centre, began searching and found conditions so dreadful that, at times, they were reduced to crawling on their hands and knees in order to spread their weight over the powdered snow.

By next morning Duff had undertaken to organise a search controlled from Braemar, in conjunction with the Glenmore Lodge control. When his group got to Corrour Bothy it was empty and the group fought their way northwards. Although radio reception was poor Duff heard on the radio that something had been found on the Ben Macdhui/Cairn Gorm plateau, but whether it was a body or a survivor was unclear.

Catherine Davidson began hill-walking at the age of 14 and was climbing at 16. She attained a very high level of climbing set by the Scottish Mountaineering Club and, in snow and ice conditions, she had reached an advanced grade three standard. She had been on Cairn Gorm in three winters up to 1970-71. She had planned to take a mountaineering instructors' certificate and a Winter Leadership Certificate.

Davidson, who was 20, was not a member of the school staff but had joined the expedition to assist Beattie, who ran the school's mountaineering club. The club held monthly meetings which involved leaving Edinburgh on a Friday evening, either to camp or stay in a hut for the weekend while climbing or hillwalking. Equipment and specialised clothing was supplied by Laggania, although the children provided their own trousers and sweaters. The equipment they carried included rucksacks, Icelandic sleeping bags, boots, extra socks, balaclavas, cagoules, over-trousers, knee-length canvas gaiters, ice axes, crampons, polythene bags which covered the sleeping bags, maps, compasses and torches. What they lacked was the experience to be out in such atrocious conditions, where the weather turns vicious with alarming suddenness.

Unable to reach the Curran Bothy, Davidson decided the group should bivouac, although she was unaware that it was a major snow accumulation area. In total whiteout conditions the children huddled together, with Davidson, in sleeping bags and polythene overbags. ''Had she stuck to her original bearing to the bothy,'' said Duff, ''she would almost certainly have found it, as it was not buried in the snow.'' Davidson tried desperately to prevent the snow from burying the children. During the night they tried to keep their spirits up by singing, but the snow began to cover them and they began to panic. One boy had only his head sticking out from the snow.

When daylight arrived, one boy was completely buried, but could still be heard shouting; two girls were out of their sleeping bags, lying on the surface of the snow, while another girl was still in her sleeping bag but half-buried. Sheelagh Sunderland was still conscious, but was dazed and unable to help anyone. Davidson, along with one of the boys William Kerr, tried to go for help but, after setting out towards Cairn Gorm, the weather forced them back. They waited all day with each other, and the conditions failed to improve. In the pitch black of night they saw the light of flares, from the Glenmore Lodge parties; they screamed but no one heard. Another girl became completely buried. The rest of the group could still hear the occasional shouts from one of the boys buried in the snow.

By dawn on Monday most of the party were either completely or partially buried, and several were probably dead. Davidson was on the point of collapse. She decided to set out again, on her hands and knees, and soon spotted a rescue helicopter, which appeared through a gap in the clouds. The pilot spotted her orange jacket and picked her up. ''Feith Buidhe'', ''buried'', and ''burn'', was all she could manage to say. It was enough to pinpoint the area. Sheelagh Sunderland, Carol Bertram, Susan Byrne, Lorraine Dick, William Kerr, and Diane Dudgeon all died. Davidson and Raymond Leslie survived the worst tragedy in British mountaineering history.

When Duff, who is now retired, and lives in Braemar, finally arrived at the site where the youngsters had collapsed, his group soon uncovered the bodies which were buried in the snow. Dr Tom Stewart, who was part of the rescue team, concluded six of the party were dead. ''The seventh and last body,'' said Duff, ''moved his hand as he was being moved, and there were faint signs of breathing. Tom immediately took charge of him.'' Duff had taken a large down parka with him, designed and made for use on Alaska's highest mountains, and he wrapped Leslie in that and placed him on a stretcher. After what seemed like an age the boy was flown direct to Raigmore Hospital, where he fully recovered. Davidson also recovered. ''At the bivouac site,'' said Duff, ''the situation changed from a search-and-rescue

mission to a police enquiry into the sudden deaths of six children.''

''I decided to leave them in situ overnight,'' he added, ''because to carry them to the nearest road end in the conditions and in darkness would have been a task well beyond our capabilities. We carried the bodies a few yards to a small rise where there was less chance of them being buried deeply, covered them as best we could, marked the site with avalanche probes and made our way off the hill.''

The inquiry into the deaths started on February, 8, 1972, and lasted for six days. The majority of the evidence centred around the planning and desirability of such school expeditions. At the end, a formal verdict was returned on the six deaths, and no blame was apportioned, although the jury made several recommendations. The inquiry was not a search for a scapegoat, but, even with the benefit of hindsight, experienced hillwalkers could see there were serious misjudgements. ''To be honest they were virtually dead before they set off,'' said Duff. ''It was simply a badly planned expedition. I've spent my life picking up bodies out the mountains, but with children it's different. They were such needless deaths. It was such a terrible, terrible waste of young lives.'' n

A Bobby on Ben Macdhui, by John Duff, is

published by Leopard Magazine, priced (pounds) 9.50, on November 7.