The world's great powers have waged discreet war in London's streets. This conflict has been played out in leafy parks, tube stations, office blocks, bars and even chain restaurants. The Secret City charts locations where the course of history has been altered, from the early 20th century to the present day through assassinations, arrests and assignations. Our survey of illicit activity takes the reader on a tour that includes mundane street furniture used as dead letter drops, exclusive apartment blocks that were home to double-agents, and the 'irredeemably insecure' building that was formerly MI6 headquarters.