Original Documents from the National Archives, Kew : Codebreaking 1914 - 1918

     With the help of captured German code books the British Admiralty was able to decypher a large
     amount of German Naval W/T traffic since the end of 1914. The organisation for this was located in
     the old Admiralty building, Room 40 (For a general history see : Patrick Beesley, Room 40, Oxford 1984).



   HW 3/3 - Clarke's history of Sigint in Room 40, 1916-1919, with appendix written by Captain Hope, 1948-1959 :

     Winston Churchill founds Room 40 " ... to penetrate the German mind and movements ...", Nov 8, 1914, 4 pages  



   ADM 137/4156 - Signal code book captured from cruiser MAGDEBURG, Aug 1914 by Russians and handed to Room 40, Oct 1914 :

     Signalbuch der Kaiserlichen Marine, 11 pages  



   ADM 137/4389 - Handelsverkehrsbuch (HVB) :

     Handelsverkehrsbuch, 8 pages  



   ADM 137/4377 - Allgemeines Funkspruchbuch (AFB) captured from U-boat 110 :

     Allgemeines Funkspruchbuch, 9 pages