A black and white film begins. It is clearly modern, but nostalgic in quality, meant to evoke the look and feel of Second World War film reel. To the tinny strains of “The Maple Leaf Forever,” a narrator begins to tell the story of HYDRA, a highly secretive and secure World War II communications facility housed at Camp X in Oshawa, which allowed the Allies in London, Washington, and Ottawa to exchange crucial intelligence with each other in the war against the Axis powers. The footage flits from “plucky Canadian engineers” erecting antennae, to a spindly-legged Rockex encryption device, to teletype operators sporting victory rolls, and to massive banks of antiquated-looking radio equipment. HYDRA, the narrator intones, was of “vital” importance to the war effort, and it continued to “provide Canada with important signals intelligence and communications for many more years” after it was transferred to the Diefenbunker near Ottawa. The camera then hovers over HYDRA communications equipment, now housed at the headquarters of the Communications Security Establishment (CSE). The wartime machinery has become a museum artefact, serving as a “reminder of CSE’s long-standing mission to provide and protect information, through leading edge technology, through synergy with our partners.”
The film itself is a curious artefact of sorts. For years, the existence of the CSE, Canada’s signals intelligence agency, was unknown to the public. Even after an investigative news team from the CBC uncovered the existence of the agency in 1974, it was not officially acknowledged by the Canadian government until 1983. Its history, too remained shrouded in secrecy. In one instance, the CSE attempted to block an institutional historian at the Department of External Affairs from publishing an account of Canadian wartime signals intelligence efforts. Now, in an interesting reversal, what once was a closely-guarded secret for the CSE is presented as a point of pride. The HYDRA newsreel film is just one part of a larger, celebratory exhibition on the history of the CSE, on the agency’s website, featuring videos, artefacts, historical sketches, and documents.
Yet despite this seemingly public reckoning with its own history, the CSE leaves much of the story untold. The newsreels and historical sketches on the origins of signals intelligence in Canada are lean on detail. And for the most part, these brief sketches leap right from the 1940s to the present day, skimming over the largest part of the history of the CSE generally and signals intelligence in Canada more broadly. The HYDRA newsreel is somewhat unique in that it nods to the Cold War and the Diefenbunker. But before one can ask how it came to be buried in a nuclear bunker under miles of earth and concrete, the film abruptly ends, and the HYDRA equipment is reduced to obsolete tech in a display case. Disconnected from greater signals intelligence systems. Divorced from greater historical context. Inert, and tame.
As the following briefing books will show, HYDRA was a far more complex and unwieldy creature than this film would imply. True, HYDRA was built by Canadians but it was a British operation until 1947. While Canada assumed Control of the HYDRA station, maintaining the network still required close collaboration between Canadian and British officials. The efforts were worthwhile. HYDRA was not just an important part of Canada’s postwar intelligence and communications infrastructure, but a key that opened the door to postwar intelligence sharing agreements between Canada, the United Kingdom, and the United States. Later, it would be part of the strategic warning infrastructure used by these partners (the Tripartite Alerts System).
Throughout its life, HYDRA was also a creature of many masters. Indeed, the CSE (then CBNRC) was both producer and beneficiary of the intelligence and communications carried over the network. But within Canada it also served the Department of External Affairs, and it was maintained and operated by the Department of National Defense - an arrangement that was not without some tension.
As the Cold War intensified and the threat of nuclear war grew, it became increasingly clear that the HYDRA was a fragile creature, not only subject to interruption, but vulnerable to attack. By early 1961, plans were underway to move HYDRA to the Diefenbunker. But what is less certain is whether these plans ever came to fruition.
Ultimately, both the tape relay centre at Leitrim and the transmitting facility at Oshawa were shuttered. From the documents available, it appears HYDRA moved to Rockcliffe – but this too is ambiguous. The final telegram in this document series bears a handwritten notation indicating that the name “HYDRA” had been all but forgotten by 1971. Did HYDRA cease to exist, its tendrils severed? Or were its limbs simply reformed, repurposed, and transformed into an entirely new creature? While these questions remain, the following briefing books reveal the shape of HYDRA from 1946 to 1971.
 Communications Security Establishment Film Unit, “Artefacts of CSE – Episode 2: HYDRA and ROCKEX,” Communications Security Establishment, https://www.cse-cst.gc.ca/en/history-histoire/artefacts-objets/episode-2, accessed 14 August, 2019.
 Communications Security Establishment, “Artefacts of CSE – Episode 2: HYDRA and ROCKEX”
 Wesley Wark, "Cryptographic Innocence: The Origins of Signals Intelligence in Canada in the Second World War," Journal of Contemporary History. 22, no. 4, 1987: 641.