British explorer Sandy Irvine's foot discovered 100 years after he vanished on Everest

Remains believed to belong to a British explorer who vanished more than 100 years ago while climbing Mount Everest have finally been found.

Andrew Comyn "Sandy" Irvine, aged 22, disappeared along with the mountaineer George Mallory in June 1924. The pair were attempting to become the first people to scale the world's highest peak.

It's still a mystery whether they succeeded in their goal before they died. Mallory's remains were discovered in 1999, which were missing a photograph of his wife that the climber had planned to leave on the summit. Irving, who had been carrying a Kodak camera that may have recorded a possible historic summit, was never recovered. The summit was officially first reached 29 years later, when Edmund Hillary and Tenzing Norgay scaled Everest from its south side in 1953.

Now, a National Geographic documentary team, including the Oscar-winning director Jimmy Chin and the climbers and filmmakers Erich Roepke and Mark Fisher, have found what they believe is Irvine's foot.

Encased in a boot and wearing a sock stitched with his name, the foot was discovered on Everest's Central Rongbuk Glacier, further down the mountain from Mallory's remains.

"I lifted up the sock," Chin told National Geographic, "and there's a red label that has A.C. IRVINE stitched into it."

Irvine and Mallory were last seen on June 8, 1924, as they set off to scale the summit. One of their expedition teaMMAtes, Noel Odell, reported spotting the two near the second of the mountain's three steps as two tiny black dots. One of the dots broke past the skyline during a brief parting of the clouds, then they disappeared.