Government Code and Cypher School: Signals Intelligence Passed to the Prime Minister, Messages and Correspondence

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 on North Africa: the German Naval Command in Africa's summary for March 11, including a conclusion that a large Allied air attack on this day, like a similar attack on March 4, indicated that the intended Axis convoy routes were now known to the Allies; the Tunis Air Corps' report for March 13 also reaches the same conclusion as the German Naval Command in Africa; on the compromising by the Allies of BONIFACE/ULTRA sigint material by action on activities; and a reply from Woolley via Special Communications Unit (SCU) Algiers on March 13.