War Office Military Intelligence (MI) Sections in the First World War
MI1 Secretariat
MI1a Distribution of reports, intelligence records.
MI1b Interception and cryptanalysis.
MI1c The Secret Service/SIS.
MI1d Communications security.
MI1e Wireless telegraphy.
MI1f Personnel and finance.
MI1g Security, deception and counter intelligence.
MI2 Geographical information
MI2a The Americas (less Canada), Spain, Portugal, Italy, Liberia Tangier and the Balkans.
MI2b Ottoman Empire, Trans-Caucasus, Arabia, Sinai, Abyssinia, North Africa less French and Spanish possessions, Egypt and The Sudan.
MI3 Geographical Information
MI3a France, Belgium, Luxembourg, Morocco.
MI3b Austria-Hungary and Switzerland.
MI3c Germany.
MI3d Holland, Norway, Sweden and Denmark.
MI3e Military translations.
MI4 Topographical information and military maps
MI5 Counter-espionage and military policy in dealing with the civil population
MI5a Military policy on foreign workmen on war service.
MI5b Counter-espionage in British possessions overseas.
MI5c Civilian passenger traffic to and from UK and ports intelligence.
MI5d Military policy and civil population.
MI5e Counter-espionage special duties.
MI5f Military records of foreigners, misc duties.
MI6 Legal and economic section dealing with the MI finance as well as economic intelligence and personnel records. Monitoring arms trafficking
MI7 Press censorship and propaganda
MI8 Cable censorship
MI9 Postal censorship
MI10 Foreign Military Attaches
MIR Information on Russia, Siberia, Central Asia, Persia, Afghanistan, China, Japan, Siam and India
Jeffrey Keith, Military Intelligence following WWI in Robertson KG (Ed) British and American Approaches to Intelligence, 1987, Macmillan pp 81-82
Thwaites Maj Gen Sir W, Historical Sketch of the Directorate of Military Intelligence During the Great War, 1921, WO 32/10776 in The National Archive.
