23 August 1957: Dean to Crean

In addition to signals intelligence-sharing and diplomatic traffic, HYDRA also became part of a strategic warning system between Canada, the United States, and the United Kingdom. In this letter to G.G. Crean (External Affairs), P.H. Dean (affiliation unclear) outlines how the Tripartite Alerts procedure should be put to “practical effect.” Dean highlights the fact that alerts need to be established on an unbroken 24-hour basis, and that HYDRA, the main line of fast, secure communications between Canada and the U.K. can be subject to outages in periods of ionospheric disturbance. Dean suggests that an additional dedicated undersea cable circuit be established between Canada and the U.K. to handle alerts traffic.