Lhotse is the fourth highest mountain on the planet. Alongside Everest to the north, and Nuptse to the west, it forms a hulking horseshoe of rock and ice that towers over Nepal’s famous Khumbu valley.

This month — maybe in the next week — a 35-year old Englishman hopes to reach the 8,516-metre summit, traverse to the edge of Lhotse’s 3,300-metre south face, one of the biggest walls on Earth, and jump off.

If it goes to plan, Tim Howell will free fall for up to 450 metres before his fabric wingsuit begins to glide him away from the wall at a ratio of 2.3 metres forward to 1 metre down. Hurtling head first through the thin air, his arms stretched out behind him, he will reach speeds of more than 230km per hour. In total, he is likely to “fly” for about three minutes, dropping 3,000 vertical metres, before he opens his parachute 200 metres above the ground and lands, into the wind, roughly 6km from where he started.