Centenary History

Defence of the Realm

"The Defence of the Realm: The Authorized History of MI5" was published in 2009 to coincide with our centenary. 

The first and only authorised history of the Security Service, it was written by Cambridge University historian Professor Christopher Andrew and published by Penguin Books. 

The book documents the work of MI5 from its establishment in 1909 right up to the point of publication. 

Professor Andrew was appointed as MI5's official historian in December 2002. In writing "The Defence of the Realm", he was given virtually unrestricted access to the Security Service's archives and no restriction was placed on the judgements he arrived at.