British Naval Intelligence Through the 20th Century


British Naval Intelligence Through the Twentieth Century. By Andrew Boyd. Seaforth Publishing, Barnsley, 2020. ISBN 978-1-5267-3659-8

Reviewed by David Hobbs

ANI members will know Andrew Boyd from his previous book, The Royal Navy in Eastern Waters; Linchpin of Victory 1935-1942.  He served in the RN as a submariner before joining in the UK Foreign and Commonwealth Office and then earned a DPhil in naval history from the University of Buckingham in 2015.  His extensive research into to a subject that has not, previously, received the level of comprehensive detail and scholarly analysis that it deserves has led to an unusually large book with 673 pages of text, 65 pages of source notes and 24 pages of bibliography.  I can only describe the result as exceptional.

Boyd’s research into the latest material to be released into the public domain has given him fresh insight into the evolution of intelligence matters in all their forms and adds a new dimension to virtually every naval operation of the twentieth century.  Those who wish to understand the full picture, therefore, must place this book alongside others considered as standard works for decades such as those by Stephen Roskill and G. Hermon Gill.  Andrew Boyd combines a naval officer’s professional understanding his subject with an outstanding historian’s ability to weave it into the wider picture.

The book is divided into five sections which cover the creation and expansion of the intelligence community, the First World War, the interwar period, the Second World War and the Cold War.  Readers should not assume from the title that this book is limited to UK-based activities; for the greater part of the period covered by the text the definition of  the adjective ‘British’ was used in the sense referred to in the Declaration of the Imperial Conference of 1926 in which the inhabitants of the Dominions, equally with those of the UK, were described as ‘British Subjects’.  Further clarification was provided in the Imperial Conference of 1937 when it was stated that this term did not mean ‘subjects of Great Britain’ but described all subjects of His Majesty in whatever part of the Commonwealth they lived.  During the two world wars, the RAN, RCN and RNZN came under the operational control of the Admiralty and there is, therefore, much in this book that is relevant to the naval history of Australia.  A number of Australians are mentioned, among them Paymaster Lieutenant Eric Nave RAN who served with the RN China Fleet as an intelligence officer after having gained the highest mark ever recorded by a naval officer in the Japanese interpreter’s course.  Captain Guy Gaunt RN, an Australian who served as the British Naval Attaché to the USA from 1914 and assumed an important position in the wider intelligence community is another.

What struck me most about Andrew Boyd’s appreciation of how naval intelligence evolved was that some disciplines have been overemphasized in previous works of less depth.  He explains, logically, that the elements that led to a comprehensive understanding of an enemy’s intention, ability and means of waging war came together gradually as experience was gained.  The essential factor was not the gathering of material from differing sources but the ability to analyse it and fuse it into what eventually became the Admiralty’s operational intelligence centre and its various out-stations during the Second World War.  Raw decrypts were of little value unless they could be placed in their proper context.  He describes the growing importance of Signal Intelligence, Sigint, in the early twentieth century, which includes both electronic and communications sub-specialisations; the latter referring to the analysis of material passed by cable, wire or radio.  Code-breaking, whilst clearly important, was actually no more so than traffic analysis, photographic reconnaissance, the fitting HF/DF to Atlantic escort vessels, the skilled interrogation of prisoners of war, human intelligence by a small number of resourceful agents or operational research.  The latter discipline was the application of evidence-based analysis to improve operational decisions.  Descriptions of prisoner interrogation, especially that of U-boat personnel, are fascinating.  The UK Government Code and Cypher School eventually contributed processed intelligence to the Naval Intelligence Division of high quality that revealed the stereotyped nature of U-boat tactics, for instance.  In operational terms this was too ‘stale’ for use in real-time operations but allowed uniform countermeasures to be developed, taught and implemented by Western Approaches Command.

Aerial photographic reconnaissance was one of the most important intelligence assets introduced during the months just before the Second World War.  This was a technology at which the RNAS had once excelled but which the pre-war RAF had allowed to atrophy and the Admiralty fully supported the Secret Intelligence Service as it attempted to fill this vital gap.  It encouraged the work of Sidney Cotton, an Australian who had served in the RNAS during the Great War and who contributed more than anyone else to the development of the capability.  Unfortunately the RN was politically barred  from operating its own photographic reconnaissance aircraft but the RAF did eventually take on the role with growing success and much of the information it provided was used to gather naval intelligence.

Arguably, the Admiralty’s operational intelligence centre, situated under the blockhouse built next to the Admiralty buildings in central London became the finest strategic assessment facility in the world by 1945 and the reputation it had gained, together with other elements of the British intelligence community across the globe, enabled the RN to remain a significant force throughout the remainder of the twentieth century.  As the control of defence intelligence became a fully joint rather than single-service matter from the 1960s, naval intelligence played an important part in defining the structure and purpose of the new organisation.  This was especially so with regard to the submarine force and its Cold War operations which included definition of the need for, and the capability required from, the UK submarine-based nuclear deterrent which has been operational without a break for over fifty years.

There is so much in this book that a mere summary does not give space for comment on more than a tiny fraction of its content.  I can say without hesitation, however, that it is a masterly history of British naval intelligence that deserves to be placed in the essential category.  This book brings a new dimension to the historiography of naval operations in the twentieth century and I recommend it unreservedly.


Please enter your comment!
Please enter your name here