Originally published in November 2021. My free subscriber base has grown twenty times over since then. Please consider supporting my work with a premium subscription.
Alexander Guthrie Denniston was an expert in German literature teaching at the British Navy’s Osborne prep school when the First World War broke out. Offering his services to the Admiralty, he was swiftly enrolled in a new, secret program directed by the First Lord himself, Winston Churchill. Housed in Room 40 of the Old Building at Whitehall, the project would use radio signals collection, cryptology, and direction-finding to spy on German communications. Denniston’s work would directly impact the course of the war. Then, in 1919, he managed the drawdown of wartime operations into a new Government Code and Cipher School that would maintain Britain’s intelligence skills by spying on diplomatic traffic throughout the interwar period. With war looming again in 1938, he was instrumental in the build-up at Bletchley Park that would prove so crucial in breaking German COMSEC once again. After his retirement in 1944, the operation would evolve into GCHQ.
At heart, Denniston was an information bureaucrat. Years after he retired, when he was asked to recall his interwar work in a lengthy magazine article, Denniston wrote without notes — for any such records would have been destroyed — yet he could recall the exact number of typists in his pool. A man of his class in a class-conscious country, Denniston never betrays an ego in his writing. Rather, in the declassified report of his work as a translator during the surrender of the German fleet in 1919, Denniston writes of old friends, now veterans, asking what bit he did during the war, and that he had to lie to them. Secret careers are not a good fit for narcissists.
Both the article and the report mentioned above, as well as Denniston’s declassified internal history of Room 40, are included in Thirty Secret Years: A.G. Denniston’s Work in Signals Intelligence, 1914-1944. Along with declassified cables regarding his work in the Second World War, they make up the bulk of the volume. His son Robin, whose name appears as the editor on the cover, merely adds an introduction and some remarks on family life. It is a hybrid memoir of a career that was almost unheralded in Denniston’s own lifetime, and whose accomplishments left an outsized impact on the outcome of both world wars.
Denniston gives exactly one insider narrative of a famous event in the history of Room 40: the moment he learned that the German cruiser Magdeburg had run aground, and that the Russians had recovered the ship’s code book, sharing it with London. It was the first of a series of lucky breaks that would help Room 40 decode and exploit all forms of German radio traffic. But there were so many other important missions. For example, German ships laying or clearing sea mines would dutifully report home as they finished; acting on the information in their intercepted signals, minesweepers or minelayers could be dispatched to reverse their work. By 1917, the Admiralty could steer convoys around the locations where u-boats had been located by radio triangulation of their position reports back to Germany. Jamming, spoofing, and rudimentary tracking of Zeppelins by their radio signals allowed an early form of electronic air defense twenty years before the development of radar. The role of Room 40 in the Battle of Jutland is well-known, too.
Yet Denniston has nothing to say about any of this. The only operational tale that he tells is the one you can see on display at GCHQ in London today. Nor should we expect Denniston to ever write down any observations about those campaigns. Not only would he be violating the Official Secrets Act, such disclosures would be déclassé, a social disaster. Denniston’s working life surrounded him in an exclusive kind of society, one that can only exist in an artificial habitat created by technocracy. He was a creature of Edwardian modernity, directly stitched into all its complex British fabric.
The organization in which he spent three decades spying for his country began as a literal cabinet operation under Churchill. Room 40 would struggle to overcome his legacy of micromanagement until 1917. Jellicoe did not have the full context of what Room 40 knew on the eve of Jutland because the interface between strategic and operational intelligence was fundamentally flawed.
As Denniston relates, Room 40 was a response to the instant problem of secret work in bureaucratic environments. Office space was understandably crowded at Whitehall. After one of the many assistant secretaries wandering the halls took umbrage at being denied admittance to the operation’s work space, they were re-housed in a place less busy, where walk-in traffic was easier to control. Working in watches, a small, insular society became very close to one another. In the years after the war, when Denniston led the project of reading diplomatic traffic related to the Washington Naval Treaty negotiations, this solidarity resulted in “a closing of ranks and a paranoid suspicion” of political agents using and abusing their work product.
This activity has always required special spaces. A pneumatic tube eventually supported rapid interoffice communications. Cryptographers frequently tucked their work away and huddled in a “small box-like room” where their work could not be overheard by naval personnel receiving intelligence briefings. Literal eavesdropping — with a stethoscope or a glass — was more than a Victorian charm, as British intelligence agents were actively using such means all around the world. Over time, the need for secret spaces has led to the development of structures proofed against electronic eavesdropping.
The modern SCIF (Secure Compartmentalized Information Facility), a kind of electromagnetic fortress used for secret conversations, is a direct descendant of Room 40. Denniston thrived in this constructed human habitat. A modern man, he hired lots of women to do what amounted to office work; as a result, he worked side by side with his wife at Bletchley Park, the union which made Robin. Despite the name changes, Room 40 became a tribe, one with its own language and culture and rituals, that still exists today.