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 correspondence: a reply of the First Sea Lord (ISL) to a query on a report of October 5, on German plans to use neutral merchant ships acquired in Spain to run a Gibraltar blockade and supply forces in North Africa (and possibly Crete); information to Flag Officer Commanding North Atlantic (FOCNA) 429; information to FOCNA 775; information to SO(I)Gibraltar; information to SO Force H764; that the ship is to be intercepted when she leaves Spanish waters, interception there being politically undesirable.