A file of signals intelligence reports, messages, and correspondence issued by the Government Code and Cypher School and sent by the head ('C') of the Secret Intelligence Service (MI6) to the Prime Minister, Winston Churchill. This file includes the following reports: a German secret service report from Finland that seventy-five British transport aircraft had brought troops to Kandalaksha; a 5th Air Fleet request for information about the housing of aircraft on Finnish territory during the winter; a report that the 17th Army was attacking Kharkov, and that the 1st Panzer Group and the 6th Army were fighting strong Russian attempts to break their encirclement; a communiqué from German Air Force (GAF) operational staff to the air attaché with a German general in Zagreb summarising Western and Eastern Front activities; and a description of a mine-laying operation, possibly between Thessaly and Leros, by the auxiliary minelayer Bulgaria.