“Just a wee bit further now,” said Dougy, stepping backwards into space and vanishing from view. I clung to a slimy branch and peered after him. He was already 50 feet below me, abseiling down the crumbling cliffside on an old nylon rope. We had descended 200 feet and there was still no water visible through the forest below us, although there was no mistaking the thunderous noise echoing off the sandstone walls of the gorge.

I had met Dougy, an ex-gillie and professional fly-fishing instructor, while fishing on the river Tay in Perthshire the week before. By the end of that afternoon, he had offered to lead me—on the strict understanding that I would not reveal its precise location—to his “secret hidey-hole,” a stretch of highland river containing so many salmon that it was almost possible to scoop the fish from the water with a landing-net. He added that