Being, as you might imagine, of an advanced age and sedentary temperament, even reading about this activity is too stressful for me. It is one of a number of adventure sports like white-water rafting and bungee jumping which have grown up over the past decade or so. Gorge-walking is one of the newest, only beginning, I am told, two or three years ago. It is a smaller-scale version of the longer-established canyoning, but which is better suited to the gentler scenery of British mountains, at first mainly in Wales but now also in Scotland. When you gorge walk you follow a stream or small river, not just its general course, but the actual flow of the water. This is fine when the stream is just a foot or so deep, provided that you can keep your footing on slippery rocks, but you are often forced to swim through rough water as the depth increases or negotiate rapids. The real fun starts when you encounter a waterfall: there’s no question of going round, you just have to jump. It’s guaranteed to leave you tired, wet, cold and probably rather scared. Gorge-walking is regarded as a dangerous sport, requiring qualified guides and instructors.