Somewhere deep in the archives of Brazil’s Police Intelligence Department there is a curious file about the highly suspect activities of a mysterious gringo. He stands about 5ft 10ins, is slim to the point of emaciation, he had a not very convincing beard, short fair hair, and all witnesses agree that his eyes had a wild and hunted look.

The first reports came in from that utterly respected source, the honorary British Consul at the river port of Manaus, some 1,500 miles up the Amazon. The suspect had called to see him, on the spurious grounds that the Americano in Manaus was safe. The consul’s secretary said her employer was not a reading man, and then offered to call a doctor. The suspect had received her news with despair, clutching his hands to his head and groaning miserably. He tottered from the shipping office (which is the consul’s main interest), muttering darkly that no doctor could help his ailment.

The next victim was the manager of the Lloyd’s Bank office in Manaus. Again this emaciated gringo figure, almost certainly English, asked desperately to exchange some books. He was told the only books Lloyd’s were interested in were ledgers, and with another terrible cry of despair (the archives are precise