In 1977 he travelled by jetboat up the Ganges to its source in the Himalayas

In 1977 he travelled by jetboat up the Ganges to its source in the Himalayas. He spent two years as New Zealand’s High Commissioner to India, where he rekindled his friendship with Tenzing. The Sherpa had enjoyed some success, establishing a mountaineering academy and travelling. But he envied Hillary, and was lonely and embittered when he died in 1986.If Tenzing never won due recognition, Hillary has repaid his debt to the Sherpas many times over. He has raised money for schools, hospitals, bridges and airfields in the Everest area, supervising much of the development work The region and its people are precious to him. His shelves are stuffed with volumes about Tibet, India and Nepal.

The house is decorated with ornaments and artworks from that part of the world. On the coffee table is a copy of The Art of Happiness by the Dalai Lama. Last year Hillary made television advertisements for the Indian Tourist Board, and refused payment.Nepal was also the scene of his greatest tragedy. In 1975 his wife and 16-year-old daughter, Belinda, were killed when their small plane crashed near Kathmandu Hillary suffered years of depression and drank heavily. He credits his Sherpa friends with pulling him back from the brink. In 1989 he married again, to June Mulgrew, the widow of Peter Mulgrew, a friend and fellow adventurer who died in a plane crash at Mount Erebus, in Antarctica, in 1979.Hillary has an awkward relationship with his son, Peter. Pat Booth, his unofficial biographer, suggests he was a distant, aloof parent, much like Hillary’s own father.

Peter, now 47, is a mountaineer and trekking guide who has climbed Everest twice – which reportedly did not impress his father I ask Hillary if he gets on well with him “I get on well with him,” he says. “I get on particularly well with Sarah [his surviving daughter]. Peter and I are very different people.” Hillary appears oblivious to the implied slight. In his autobiography, View from the Summit, he describes Belinda as “the closest thing we had to a perfect child” One wonders how Peter and Sarah felt about that. Hillary says he did not realise that they went through hell, too, after losing their mother and sister He says: “I don’t find it easy to warm to people. I’ve really found it difficult to have close friends.”The exception seems to be the Sherpas. He is forsaking a grand dinner in London, hosted by the Royal Geographical Society and attended by the Queen, to spend the 50th anniversary of the ascent in Kathmandu.

All other surviving members of the expedition are going to London, where they will relive the climb. “Except that they won’t be able to describe the summit bit very well,” chortles Hillary. “I’m fonder of my Sherpa friends than the majority of my old team-mates. They’re more important to me.”Hillary deplores the commercialisation of Everest, particularly the guided trips that have created human traffic-jams on the mountain and turned it into a gigantic rubbish tip – abandoned tents and oxygen bottles litter the slopes, together with frozen corpses.