With the heavy sledges sinking into soft summer snow, progress was extremely slow. At one stage they crawled just 400 yards over eight backbreaking hours. As both teams relayed supplies over the same ground, they became more and more exhausted.

The endless white expanse ahead was broken only by dangerous crevasses and high ridges of snow. And without a visible goal on the horizon, the overloaded dogs had no motivation. Frustrated with their slow progress, worried about failing Shackleton and determined to stay ahead of Joyce, Mackintosh began to whip them constantly. His strategy backfired and his dogs rebelled.

As they advanced south, the cold became more piercing. It made sledging easier, but the men suffered as their clothing became soaked with sweat in the day and froze at night. One stretch to Bluff had taken ten days of hard slog. Shackleton’s expedition had covered the same ground in two or three.

Mackintosh was worried. On 11 February, he announced that he would take Joyce, Wild and the nine best dogs on to the next depot, sending the other men and dogs back to Hut Point. The southbound party struggled on through howling gales, plagued by ice-encrusted beards, frost-nipped feet and weeping blisters.

They reached Rocky Mountain Depot at 80º on 20 February and celebrated with a mouthful of brandy before building snow mounds to guide Shackleton in. Disappointingly, they had only managed to get between 105 and 135 pounds of supplies to the depot, instead of the planned 220.