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 contains a message from the Chief of the Imperial General Staff (CIGS) to the Prime Minister (PM) with an explanation of the German operations, including Neptune, on the southern Russian Front, on April 2; the text of a message sent to Moscow, on April 2; and a report on the German Air Force's (GAF's) preparatory moves for Neptune, on March 30, with the PM's query to the CIGS.