Everest diary: Dingboche: What makes us risk all for a mountain

WHAT MAKES someone so set on climbing Everest that they are prepared to spend pounds 25,000 and risk their life for a goal that has already been achieved by more than 700 others?

Byron Smith and Rob Owen, two of my companions on the Himalayan Kingdoms Everest expedition, have no time for the cynics who say that paying to climb the mountain by the popular South Col route is "dog on a leash" stuff where guides and Sherpas do the hard work.

"It's still my legs and lungs that will get me up there," says Byron in his rich Canadian accent.

"It's just jealousy when people talk about it being a long yak route. They're just trying to belittle you to make themselves feel better."

Byron and Rob, like me, are on their first trip to the Himalayas. Unlike me, they had both made Everest a personal goal some time ago and are set on seeing it through.

For me, the expedition is a dream assignment, getting to the summit of the world would make me pretty chuffed, but it is the whole mountaineering experience that matters.

Byron would probably find this attitude somewhat negative. When I asked the pair if they have thought of climbing other lesser peaks in the Himalayas for starters, the answer was an emphatic no. "To me, Everest is the ultimate symbol of challenge," says Byron.

It is the same explanation I have heard from other members of the team, and one which probably distinguishes the fee-paying clients on this type of expedition from the many groups of climbers who come out here each year to climb as friends on less prestigious but often more technically demanding peaks.

Rob Owen is a 32-year-old London stockbroker covering eastern Europe for ABN-Amro. The company will donate pounds 15,000 to the Big Orange Bus charity, helping orphans in eastern Europe, but as a skilled operator, Rob has negotiated a rugby league-style win bonus. If he gets to the top and waves ABN-Amro's flag, the charity will get an extra 20 per cent.

Rob has already demonstrated the kind of gritty determination he will need later on in the way he refused to be laid low by a gut infection. All offers to take some of his rucksack load were declined and now he seems back to his stocky powerhouse self.

An adventurer rather than a mountaineer, Rob has been on three expeditions in the Arctic, hauling sledges for up to 14 hours a day, and two years ago he climbed Mount McKinley, at 6,198 metres, the highest peak in North America. "The Arctic is an awesome experience but there is nothing more physically demanding and nerve-racking than Everest," he says.

If Rob sounds a driven man, just listen to Byron Smith, the 37-year-old owner of a Ford franchise in Vulcan, Alberta, and someone who "doesn't believe in the word can't".

A fitness fanatic, Byron bulges muscles in all directions, though he had to be advised that his brief running shorts might offend Sherpa sensitivities.

He has climbed 50 summits in the Rockies in the last six months and had originally thought of organising his own expedition to make him the 11th Canadian to the top.

He bought into the Himalayan Kingdoms Expedition purely for logistical reasons and admits he is not a natural team player.

When I wonder if that is not at odds with his success as an ice-hockey player, he sees no contradiction. "I was always the star. The team was built around me."

If hubris can get you to the top of Everest, Byron will be there. But in a piece of frank talking that could indicate friction when the tension mounts, he adds: "I won't let anyone get me off my game plan."

Both Byron and Rob are married. The Canadian says his wife Jamie understands how important Everest is to him but he is thankful his eight-year-old son Zachary doesn't appreciate the risk.

The stockbroker married Lisa last July and is hoping our summit bid could come early so that he can make a speedy return home.

Rob's biggest fear is not the altitude or avalanches, but of not getting a chance at the summit - "the fear of spending 10 weeks on the mountain and then it's not our time, and you have to accept that."

Whatever happens, he says it is going to be his last big shot. "Then I'm going to be a family man, throw away the crampons and pick up the diapers."

Perhaps that is one more distinction between the Everest challenger and the climbing lifer.