Mountaineer David Sharp told his mother she had no cause for concern when he left home to make a solo attempt on Mount Everest's north-east ridge some two months ago. "You are never on your own," he told her. "There are climbers everywhere." His words assumed a tragic significance yesterday as fellow mountaineers argued over the decision of other climbers to leave Mr Sharp as they processed towards the summit.
Alan Hinkes, who climbed Everest in 1996 and last year became the first British climber to conquer all 14 of the world's mountains over 8000m, abandoned an expensive ascent of K2, the second-highest mountain in the world at 8,611m, in the 1990s to save the life of a climber who was near collapse. But he said that any act of mercy above 28,000ft (8,500m), deep in the so-called "death zone", above which the human body deteriorates and where dozens of climbers saw Mr Sharp in trouble last week, may have been foolhardy. "You could sit with him for a few hours until he dies and then die yourself," he said. "You certainly can't carry another human being on your back at that altitude."
Mr Sharp's parents, Linda and John, of Guisborough, east Cleveland, accept that, in Mrs Sharp's words, "your only responsibility is to save yourself", despite criticism from Sir Edmund Hillary, the first man to reach the summit of Mount Everest, of those who failed to save their son. Sir Edmund said on Tuesday that the commercially motivated pursuit of the summit means people "just want to get to the top [and] don't give a damn for anybody else in distress".
Mr Sharp's extraordinary capacity to excel at everything to which he turned his hand helped convince his mother that she should believe his reassurances when he left home for Everest on 27 March. After securing excellent A-levels at the Prior Pursglove College in Guisborough, he enrolled on an engineering degree at Nottingham University, from which he graduated with first-class honours. He joined the university's mountaineering club and was soon making his first major ascent, of the 4,478m Matterhorn in the Alps.
Lenin Peak, at 7,134m the highest mountain in central Asia's Trans-Alay range, followed, then Kilimanjaro (5,895m) in Tanzania and Cho Oyu (8,201m) in Nepal. On Cho Oyu he met members of a Northern Ireland mountaineering team, with whom he made his first attempt of Everest in 2003. They reached 8,470m before bad weather forced them back. Mr Sharp tried again, alone, in 2004 but had no oxygen and was forced back at the same height.
Mr Sharp, who has an older brother Paul, 36, juggled his mountaineering with an engineering career at QinetiQ, the global defence and security agency, during which he undertook a six-month sabbatical to backpack in south-east Asia and South America.
But he yearned for a move into teaching. He had passed his PGCE and secured a teaching post from next September, before which he wanted another go at Everest. "He probably packed as much into his 34 years as some people do in a lifetime," said his mother. "[He] wanted to be top of everything and Everest was no exception."
Mr Sharp had reached the summit and had descended more than 300m down the North Face last week, a route which is technically more difficult, with more exposed rock than the Nepalese south side of Everest, when he apparently began suffering from oxygen deprivation.
The precise time of Mr Sharp's death is unclear but he appears to have decided, as some mountaineers do, to make his final push without bottled oxygen. He had purchased only two four-litre bottles - half the volume that many take for the climb - from his Kathmandu trekking agency.
Some climbers do this to reduce the weight they are carrying, while others consider summitting without bottled oxygen to be a purer achievement.
As many as 150 people are summitting Everest at one time and at least 40 saw Mr Sharp in trouble last week, including double-amputee Mark Inglis, a New Zealander, who was on his way to the top. He has defended his decision not to stop and suggested that Mr Sharp was ill-equipped.
"He had no oxygen, no proper gloves, things like that," he said on New Zealand television.
Mr Hinkes insisted Sir Edmund had no business passing opinion on the conduct of Mr Inglis and others. "He's not climbed a mountain for years and he should not say things like that," he said. "For all we know, David could have said 'I'm all right, don't worry about me,' to those who passed. You can be alright one minute and semi-conscious half an hour later. You dare not stop for 20 minutes at that altitude."
But one Sherpa appears to have tried to administer oxygen to Mr Sharp. He found him beyond help, in a crevice close to one of the main routes and near the remains of an Indian climber who died in 1997.
This gesture may have been futile but it enabled the mountaineering firm manager for whom he worked, Russell Bryce, to contact Mr Sharp's family and inform them of their son's death. "I cannot say how grateful I am to the Sherpa and Russell," said Mrs Sharp. "He had no obligation to do it."