On This Day: Britons George Mallory and Sandy Irvine vanish during attempt to climb Everest

JUNE 9, 1924: Britons George Mallory and Sandy Irvine disappeared during one of the earliest known attempts to climb Mount Everest on this day in 1924.

It is believed they may have reached the world’s highest summit - 29 years before Sir Edmund Hillary and Tenzing Norgay - and were returning when tragedy struck.

Fellow mountaineers from the Second British Mount Everest Expedition – shown in a British Pathé newsreel - last sighted the men as they got within 800ft from the top.

Neither body was found until Mallory’s frozen and remarkably well-preserved corpse was discovered 26,760ft up on the north face of 29,029ft peak in 1999.

The last trace of Irvine was his axe, found 27,760ft up, although a possible sighting of his body was made in 1975 by a Chinese climber who died hours after reporting it.

And the mystery of whether they reached the summit – and if their lost camera contains the first ever picture atop Everest - remains deeply gripping.

It rests largely on the last man to sight them, Noel Odell, who was climbing in support of the Mallory, 37, and Irving, 22, and was 2,000ft behind them.

He said he saw them on the deadliest second of three steps on the final ridge, although other Everesters doubted even Mallory – a man man dubbed Galahad – could climb it.

[Everest anniversary: 12 little-known facts about the world's highest mountain]

[Everest anniversary: World's five deadliest mountains]

When a 1933 expedition found oxygen canisters and Irvine’s axe on the first step, meaning they would be 300ft lower, Odell supposed he must have been mistaken.

Yet he remained convinced that Mallory, who wrote “perfect weather for the job” in his diary before his ascent, made it to the top with the young Oxford undergraduate.

Others believe Mallory – the more experienced of the two – went on to attempt to reach the summit alone and took Irvine’s oxygen canisters with him.

Regardless of whether either man got there, most experts believe the younger climber is likely to have died alone from hypothermia or exhaustion.

While the older man most probably fell to his death after being caught in a fierce snowstorm.

Even before his mysterious disappearance, Mallory, who was admired by the Bloomsbury Set of intellectuals and writers, had achieved a mythical status.

[On This Day: Edmund Hillary and Tenzing Norgay first to climb Mount Everest]

[Everest anniversary: Incredible achievement means fewer world firsts for modern-day adventurers]

The poet Geoffrey Winthrop Young dubbed the Cambridge graduate, who later taught at Charterhouse School, Galahad after King Arthur’s brave knight.

And poet and fellow First World War soldier Robert Graves claimed his friend had once climbed an “impossible” overhang on Mount Snowdon to retrieve his pipe.

The rock feature is now called Mallory’s Slab in honour of the climber.

Routinely risking his life, he took on a legendary status similar to polar explorers Robert Falcon Scott and Ernest Shackleton, the ill-fated stars of the age.

Those who made subsequent attempts to climb Everest benefited from improved tackle, including huge advances in breathing equipment.

Indeed, the first ascent without the use of supplemental oxygen was not achieved until 1975 when Italian Reinhold Messner and Austrian Peter Habeler realised the feat.

Since 1953, more than 3,000 people have reached the summit of Everest - mostly using breathing equipment – with around 200 attempts every summer.

However, around one in ten never make it.