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 ambassador in Moscow on the three-power conference of September 29-October 1; supplies for the Soviets were agreed but their delivery remains uncertain; and from the Japanese consul-general in Singapore on anti-Japanese measures and defensive preparations for a war with Japan.