Environmentalist Lewis Pugh, 40, wore just trunks, goggles and a swimming hat to swim 1km (0.62 miles) across Pumori Lake. The icy lake lies 17,000ft (5,300m) up the famous mountain near the Khumbu Glacier and its waters are around just 2C.

Lewis took 22 minutes and 51 seconds to breast stroke across the lake and had to find a “delicate balance” between going too fast and too slowly.

He says if he had gone too quick he could have lost energy and drowned but if he had been too slow he would have suffered hypothermia. Read more…