The Defence of the Realm

The Defence of the Realm: The Authorized History of MI5, published in the United States as Defend the Realm, is an authorised history of the British Security Service (MI5), written by historian Christopher Andrew. Andrew was commissioned in December 2002 to write the history for MI5's 100th anniversary in 2009, and was given "virtually unrestricted access" to much of MI5's files, as well as "no restriction" on whatever conclusions he decided to draw from them. The book reported, amongst other things, that MI5 kept a file (under a pseudonym) on Prime Minister Harold Wilson (as revealed by Peter Wright decades before in Spycatcher), as well as noting how many of Wilson's MP's were spying for the Soviet bloc. The book's title was derived from MI5's Latin motto, Regnum Defende. Historian Keith Jeffery was commissioned to write a similar authorised history on the Secret Intelligence Service (MI6) for release in 2010.