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 report: a German intelligence assessment of guerrilla strength in the Split-Dubrovnik area, with the assumption that the guerrillas are being supplied by Allied ships, on October 3; and a query from the Prime Minister (PM) to Brigadier Hollis (see also 4643).