Bonington's last big challenge: the secret summit of Tibet

He already has his senior citizen's rail card and will soon be receiving his old age pension. But far from relaxing into retirement in his Lakeland home, the mountaineer Sir Chris Bonington is planning arguably his most dangerous expedition - up Tibet's secret mountain. He tells Matthew Brace his thoughts about his prospects

Bonington will turn 64 in August, just days before he is due to begin his second attempt on an ascent of Sepu Kangri (6,950m or 22,800ft), a treacherous and as yet unconquered mountain in north-east Tibet. His first attempt, last May, ended in failure when he was forced back by atrocious weather. He knows that this year's expedition is almost certain to be his last big climb to this height. And he knows it will be a struggle.

The peak, whose name means the Great Snow Mountain by the Sacred Lake, lies in the eastern section of the of the Nyain-Qen-Tanglha Shan range, 400km north-east of the Tibetan capital, Lhasa. Bonington's attempt last May was the first European expedition to the area. It is one of the last unexplored regions of the Himalayas, a remote, frozen wilderness the size of the Swiss Alps, inhabited only by a few families of Tibetan nomads and their yaks. It boasts 20 peaks over 6,000m and the sources of the Mekong and Brahmaputa rivers, two of the longest in Asia.

Before the attempt he said: "When almost every range has been explored, when you can pay to be guided up Mount Everest, and most of the faces and ridges of the world's 8,000m peaks have been climbed, an unknown range in the heart of the Tibet capped by mountains of outstanding beauty provides a challenge few mountaineers could resist."

The mountain is complex and formidable, comprising extremely steep slopes, sheer rock walls and ice overhangs, and a long approach to the summit.

Bonington's team for the 1998 attempt consists of old and trusted climbing pals: the Scot Graham Little, Victor Saunders (an architect turned mountaineer), Jim Lowther and Charles Clarke, a consultant neurologist and expedition doctor. Clarke was doctor on Bonington's 1975 and 1982 Everest expeditions.

Bonington has studied records from the Tibetan Met Office spanning the past 30 years which show that precipitation goes up as summer approaches but down in the winter, so he will start in the autumn when he should get clearer skies and less snow.

Whether the weather is fair or foul, he will have to contend with the fact that age is creeping up on him.

"More and more people who are getting older are realising what they can do. There are a lot of older climbers who are still climbing bloody well."

Bonington also seems to be an older climber who is climbing "bloody well". He lives in the Lake District surrounded by opportunity and last week he was in Scotland, "just nipping up" a few mountains in the grip of winter, a gentle afternoon stroll compared to the Himalayas.

This lust for life has sustained him through his 48-year career which has seen him scale the world's great mountains including Everest, K2, Panch Chuli, the Eiger, Mont Blanc, Mount El'brus (the highest peak in Europe) and Mount Vinson in Antarctica, the summit of which he reached solo.

He will be expanding on his philosophy of adventure next week at the Royal Geographical Society when he is interviewed live on stage by the journalist Libby Purves.

The conversation may touch on the controversial issue of the ethics of exploration. No one doubts his credentials as someone who travels with respect and due care for the environment he is visiting, but will bus- loads of tourists be tempted to follow in his wake in their search for the last unexplored corners of the world?

"There aren't many places in the world like this part of Tibet - not as wild and romantic. No, I don't think it will ever become like the Alps but if climbers do go into the area and some trekking takes place as well, the local people will benefit from it financially," he said.

Bonington is realistic about his prospects on Sepu Kangri: "At the moment I seem to be pretty fit and I'd really like to get to top but I've got to be realistic. It's going to be hard for me," he said.

"As I get older things become more difficult. Carrying heavy loads is harder and I wouldn't try to climb an 8,000m peak now. As life goes on I will be forced to climb smaller and smaller peaks. Although there are plenty of great ones left at 6,000m or under, this is probably the last peak over 6,500m I will do."