A responsible operator does not send one guide with ten climbers. The guide ratio matters enormously. At Vertical Sky, our lead guide is supported by assistant guides in a ratio that ensures every climber is properly supervised throughout the expedition.

I'll tell you the exact moment I knew the expedition had worked. It was day seven, summit night, 1am, at 5,200 metres — and my leadership team did something that had never happened in our offices. The mountain made it happen.