Naval War College Review


Since the revelation of the Ultra secret in 1974, it has been widely accepted that Ultra intelligence—that is, high-grade Axis codes decrypted by a cen- tralized British interservice unit called the Government Code and Cypher School (GC and CS) at Bletchley Park—gave Great Britain a decisive advantage over its Axis foes and that this advantage was particularly significant in the battle against shipping to North Africa.