The health and safety briefing provokes looks of horror - they have already drunk copious amounts of tap water and brushed their teeth. Further enquiries reveal that they used the water in the jugs by their beds - which the hotel management assures me has been boiled and filtered. I note the need for extra Imodium and stomach antibiotics.

Tuesday I stress the need for regular fluid intakes during the day - but definitely not tap water. One client insists he never drinks before the sun is over the yard arm. I later realise his hearing aid is malfunctioning.

Wednesday A young female member of the group crawls into my tent at dawn. There is no toilet paper and would I do something about it now? I stagger bleary-eyed to the storage barrels. I had always imagined myself one day saving a damsel in distress.

Thursday The same young woman again crawls into my tent at dawn. Visibly distressed and foaming at the mouth, she appears to be suffering from rabies. I drag her outside and throw a bowl of icy water into her face. Big mistake. It turns out she simply has not cleaned her teeth since Kathmandu as she isn’t sure where to spit the toothpaste. But after three days of uncleaned teeth, she is cleaning them now - whatever the consequences.

Friday The young woman crawls about my tent at dawn looking, she claims, for the route map for today’s walk. In her hand is a bundle of postcards complete with stamps. No, she is not looking for the trail, but for the nearest high-altitude letter box. She leaves, muttering that a trek leader with a diplomatic passport ought to have access to the diplomatic bag, even at 17,000ft. When I explain that the diplomatic passport pertains to Pakistan and not Nepal, she complains:“No wonder we have no Empire left.”

Stephen Bines was a primary teacher in England until recently. He now works as a mountain trek leader in Nepal and Pakistan and holds a diplomatic passport because his partner works for the British government as an education adviser in Pakistan