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: from the Japanese minister in Sofia on Soviet espionage and Bulgarian attitudes in the Balkans, on April 13; the Japanese ambassador in Kuibyshev reports a conversation (with Molotov?) on the Neutrality Pact; and the Japanese consul in Casablanca reports on changes in the French government, on April 17.