A series of muffled raps and shakes of the tent poles was followed by the sound of the zip opening, then grubby hands thrust two cups of coca tea and a quiet buenos diaz through the open door. Outside it was still cold and 4am dark but the electric-blue washes of dawn were starting to push above the distant mountains. Extremely early mornings induce a state of quivering, adrenal, apprehension in me which fuelled me through the mechanical camping routines of stuffing body into clothes and spare clothes and sleeping material into bags. Dervala needed little encouragement to do likewise and soon we were stretching and yawning in the cool, damp air of a high mountain dawn. At a sleepy dinner the night before, Raul, our guide, had persuaded us that an early, early start would see us free of the hordes of other trekking groups. He was right, around us lay the grey toadstools of myriad tents, each full of quiet snuffling or snoring noises. Our porters were breaking camp with stage whispe...