My misery plummeted further with the unexpected barrier of a crevasse materialising in our path.

To me, it revoked the vague reassurance that the tariff of technical difficulty for the climb was negligible. Ironically, the crevasse represented descent, but a far hastier one than I craved. It also revealed the second aspect of my acrophobia – of falling helplessly into an uncharted abyss.I sat down for some minutes to contemplate the natural snow-bridge stretching across the gap, before calmly telling Abraham I would not be crossing it. It was a couple of feet wide and being ‘natural’ there was no accounting for its on-going capacity to support a human body. The depth of the crevasse remains unknown. The bridge spanning the void was the length of one long man and dipped down in the middle before rising to a steep slippery bank on the other side

I was painfully aware that I had failed to keep my footing when I had an entire mountainside to grip. True, I was attached to a professional guide, and one well-trained, I imagined, in catching stray jittery gringos. But how could rope skills defeat the laws of physics when his spare frame barely matched the weight of mine?

Two of the German climbers caught up, while I pondered neurotically. I waved them on, but they insisted I go first. The first gestured kindly enough, but I couldn’t tell whether it represented solidarity, sadism, or an opportunity for him to coldly make his own personal risk assessment. Staring at the narrow strip of snow ahead, I narrowed the focus of my gaze onto it – cropping out its surroundings from both my retina and mind’s eye. Numb with fear, I stepped forward to the brink figuring I had a one-in-three chance of falling in.