The eponymous "untouchable" is Albert William Packer, known to all as Mister. A career criminal, he dispenses rough justice on his manor without mercy, punishing any opposition terminally. When a Customs and Excise case against him is torpedoed, Packer decides to expand. Buying heroin from the Turks in London's Green Lanes no longer satisfies him, so he decides to travel to Sarajevo where he plans to negotiate safe transit through the black market crossroads that is the former Yugoslavia. But he has a nemesis: Home Office Archivist Joey Cann determines to bring Packer down and follows him and his thugs to Sarajevo.

Cann initially appears to be a loser, but the inevitable confrontation between the two men in the lethal surroundings of Sarajevo changes both their lives forever. Joey Cann is a protagonist more in the le Carré mould than Seymour's customary professional men of action, and his inexorable stripping away of Packer's sinister layers is expertly done. As always with Seymour (in such books as Holding the Zero and A Line in the Sand), the dividing line between good and evil is never clear and the moral ambiguities here are quite as satisfying as the utterly involving narrative. --Barry Forshaw