The author claims that the Fifth Man was not, as Spycatcher contends, Roger Hollis, but Guy Liddell, who was part of a mostly homosexual set of aristocratic pro-Soviets that included Anthony Blunt, Guy Burgess and Louis Mountbatten. By sabotaging a defector's attempted warning to the Americans of Japanese plans to attack Pearl Harbour, Liddell may have changed the whole course of the war.