To the modern mind, the search for El Dorado, Amazonia’s fabled city of gold, has come to symbolise the ultimate fool’s errand, even more than dredging Loch Ness for a cryptozoological monster or looking for Elvis in far-flung locations. El Dorado is the quintessential fantasy.

Andrew Lees grew up blissfully besotted nonetheless. As a bookish child in postwar Merseyside, the idea of a gilded metropolis hidden deep in the Brazilian rainforest gripped his imagination. Responsibility for this boyhood fascination fell to a certain Lieutenant Colonel Percy Fawcett. During one of their regular library visits, Lees’s father unearthed a copy of Exploration Fawcett and handed it to his son. ‘You’ll enjoy this,’ he told him. ‘It’s about an explorer who vanished without a trace in the Amazon.’

He wasn’t wrong. A page-turner incorporating frontier anthropology, botanical wonders and death-defying adventure, the dog-eared library book enchanted the young Lees. There he was with the dashing Fawcett, hacking through tropical undergrowth, fending off snakes and spiders and parleying with cannibals. And then, poof, Fawcett disappears, a mystery to beat