nRegnum Defende: Defend the Realm. MI5, the intelligence agency responsible for protecting the UK against threats to national security, has acted under this motto since it was founded in 1909. This has involved the management of secrets over the decades: secrets for which vast swathes of information are now declassified.

Detailing uprisings and executions, double agents, and femmes fatales from across the globe, The MI5 Archive presents a window into the world of spycraft that has kept British democracy safe.n nRummage through documents received anonymously to the shadowy PO Box 500, London, W2. Work out what has value and how to decode it, with experts at your shoulder: authors and archivists Mark Dunton and Stephen Twigge have had unparalleled access. Within you will find source material on the Siege of Sidney Street, the Cambridge Spy Ring, and the Profumo Affair, and never-before-published imagery prepared exclusively for this book and the National Archives' hit exhibition M15: Official Secrets.n nFrom interrogations to surveillance logs, coded messages to intercepted phone calls, The MI5 Archive charts the clandestine activities of MI5 right from its inception.n