Kevin Macdonald's BAFTA Film Award-winning docu-drama tells the astonishing story of two young mountaineers, Joe Simpson and Simon Yates. In 1985, they climbed the previously unconquered west face of Siula Grande, a peak in the Peruvian Andes. But, on their descent, Simpson fell, breaking his leg. Yates began lowering Simpson down the mountain, using two 150-foot ropes tied together. Unfortunately, during this process, Simpson slipped over a ledge and was left dangling in mid-air, unable to be lowered further or pulled back up. Yates had to decide whether to die on the mountain with Simpson, or to cut the rope. He took the latter option. But Simpson didn't die in his fall; he disappeared into a crevasse instead. Now, with Yates thinking he was dead, Simpson had to somehow get out of the crevasse and descend the glacier unaided. The film mixes interviews with the two men with a stunning reconstruction of their individual physical and emotional plights. With Brendan Mackey (as Simpson) and Nicholas. Touching the Void - Thursday at 10pm on Channel 4.