The Defence of the Realm : The Authorized History of MI5, Paperback

The Defence of the Realm : The Authorized History of MI5 Paperback

4.5 out of 5 (2 ratings)


To mark the centenary of its foundation, the British Security Service, MI5, has opened its archives to an independent historian. "The Defence of the Realm", the book which results, is an unprecedented publication.

It reveals the precise role of the Service in twentieth-century British history, from its foundation by Captain Kell of the British Army in October 1909 to root out 'the spies of the Kaiser' up to its present role in countering Islamic terrorism.

It describes the distinctive ethos of MI5, how the organization has been managed, its relationship with the government, where it has triumphed and where it has failed.

In all of this, no restriction has been placed on the judgements made by the author. The book also casts new light on many events and periods in British history, showing for example that though well-placed sources MI5 was probably the pre-war department with the best understanding of Hitler's objectives, and had a remarkable willingness to speak truth to power; how it was so astonishingly successful in turning German agents during the Second World War; and, that it had much greater roles than has hitherto been realized during the end of the Empire and in responding to the recurrent fears of successive governments (both Conservative and Labour) and or Cold War Communist subversion.

It has new information about the Profumo affair and its aftermath, about the 'Magnificent Five' and about a range of formerly unconfirmed Soviet contacts.

It reveals that though MI5 had a file on Harold Wilson it did not plot against him, and it describes what really happened during the failed IRA attack in Gibraltar in March 1988.


  • Format: Paperback
  • Pages: 1072 pages, Illustrations, col. map, ports.
  • Publisher: Penguin Books Ltd
  • Publication Date:
  • Category: History: specific events & topics
  • ISBN: 9780141023304



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Review by

An exhaustive and intriguing history of MI5 for which the author was given extensive access to the agency's archives.I found it fascinating but was often almost overwhelmed by the extraordinary amount of detail that was offered up.However, I am very glad that I read it and would definitely recommend it to anyone else interested in this field.

Review by

This is a scrupulously well researched account of the history of the Security Service MI5 and the operations in which it has been involved. The author has been given access to the great majority of historical files, while forming his own conclusions about the significance of their contents. Inevitably coverage of some recent events is less thorough due to current national security requirements and the need to protect active sources, but is still insightful and sober in its conclusions. The book will not of course satisfy conspiracy theorists of one stripe or another, but the author's judgements seem shrewd and pretty balanced to me, pointing out intelligence successes (e.g. the Double Cross turning of German agents in WWII, or the tracking down and surveillance of Islamic ricin and homemade bomb-making plotters) and failures such as the slowness in identifying the Cambridge spy ring, the over-estimation of the strength of the KGB's analysis of the intelligence they acquired from the West and more recently the relative slowness in the 1990s of perceiving the worldwide reach of Islamic terror plots. The book clearly shows the insubstantial nature of most intelligence and the difficulty of assessing its reliability, points often lost on politicians and the general public who desire certainty and clearcut information.Finally, one aspect of the book's structure was a little less than helpful, that is the fact that each major section, e.g. WWII, early Cold War, etc. began with a chapter covering how MI5 evolved during that era, before the other chapters giving the detail. This led to a slight confusion on timing in some places and some duplication of material. Usefully, there is a concluding chapter detailing the main points covered in the text. The index could have been more thorough.