The next day began slowly. Sleep had been kept away by tension, throbbing heads, unusually quick and heavy pulses, thirst and nausea. Climbing to 3,670m from 1,740m, itself a big jump from our normal altitudes, in a single day and from an already tired state, had been double what we should sensibly have done. We spent the day resting, eating everything we could, exploring the hut and campsite, mar­velling at the scale of the views down on to the glacier, across the valley and up to our summit, intermittently feeling sor­ry for ourselves and closely monitoring how much of our strength was returning.

This, it turns out, was a fair amount. Come the morning of day three, and after a better night’s sleep, we decided to climb as close to 4,000m as we felt comfortable with to help our bodies further acclimatise. We’d then rest up in the after­noon and go for the summit at 2am the next day.

The morning was crisp and cold and stunning to look out on. The distant and jagged peaks, spreading across into Russia, were sharp against the horizon. The flowing glacial water, diverted across a corner of the camp to supply the teams stopping here, was coated with a thickening crust of ice that snapped and cracked pleasingly when we drew the day’s supply. The signs were all good.

As was the day, initially. Climbing upwards across steep-sided snow slopes we made quick and confident pro­gress to well above 4,000m in well under than two hours.

We congratulated every descending party we passed who had made their attempt that morning. Even the suddenly collapsing weather – the wind picked up and heavy rains and hail suddenly began to pour down on us – didn’t suppress our spirits. By the time we’d made it back to the camp we felt certain that tomorrow we’d be on the summit ourselves.