Room 40 and German intrigues in Morocco: re-assessing the operational impact of diplomatic cryptanalysis during World War I

During World War I, Germany sought to provoke numerous insurrections throughout the British and French Empires. Examining the influence of signals intelligence within one of these colonial settings provides an opportunity to measure the operational importance of wartime cryptanalysis. Through a careful analysis of the original intercepts, this article reconstructs the responses of Room 40, the Admiralty’s cryptology department, to Germany’s Moroccan intrigues and highlights the development of intelligence practices. It argues that strategies to deploy diplomatic intelligence emerged gradually, but that Germany’s enduring support for Moroccan dissidents suggests diplomatic cryptanalysis only secured modest results within an operational context.