LONDON — The partial remains of a British mountaineer who might — or might not — have been one of the first two people to climb Mount Everest are believed to have been found a century after their ascent of the world’s highest peak, according to an expedition led by National Geographic.

Ahead of the release of a documentary film, the television channel said Friday that the expedition found a foot encased in a sock embroidered with “A.C. Irvine” and a boot that could be that of Andrew “Sandy” Irvine, who disappeared at the age of 22 along with his co-climber, the legendary George Mallory, near Everest’s peak on June 8, 1924.