For Britain's best known mountaineer, Chris Bonington, Tibet's 'secret mountain' - Sepu Kangri - was the last great climb in the world.

Sir Christian Bonington, first spotted Sepu Kangri’s remote summit from an old Russian turboprop airplane as he was en route to Lhasa in 1982. It took 14 years to gain access to this remarkable region.

Despite two near misses, Sepu Kangri remains unclimbed.

1996 - Bonington and Charles Clark are finally allowed to make a reconnaissance into Northeast Tibet. They try to find a route into the peak, guided only by a Chinese tourist map and an old photograph. The pair are the first Westerners to reach the Sepu Kangri region.

1997 - In the spring, Bonington and Jim Lowther reach 19,900 feet on Sepu Kangri only to be defeated by high winds, heavy, snow, and poor visibility. Though the continuous bad weather is frustrating, the team plans a return expedition for 1998.

1998 - In the autumn of 1998, Bonington leads a second attempt to climb Sepu Kangri. Team members Victor Saunders and Scott Muir, ultimately climb within 150 yards of the summit, reaching 22,400 feet in dangerous snow conditions and rising storm. The peak remains unclimbed.