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 the Mediterranean: that the German Air Force (GAF) in Sardinia are to investigate the suitability of additional airfields for fighters, on April 15; and that a convoy is to sail from Piraeus to the Dodecanese with 2100 troops, on April 13; Naval Headlines, covering shipping for Tunisia; from the Brazilian ambassador in Lisbon, on rumours of Allied designs on the Azores, on April 12; on the Central Russian Front: of German preparations for a Zitadelle operation, on April 13, and a query from the Prime Minister (PM) to the Chief of the Imperial General Staff (CIGS); and the CIGS' reply, on April 15.