Bletchley Park was the central site for Britain's codebreakers during World War Two. Run by the Government Code and Cypher School (GC&CS), it regularly penetrated the secret communications of the Axis Powersmost importantly the German Enigma and Lorenz ciphers. The official historian of World War II British Intelligence has written that the "Ultra" intelligence produced at Bletchley shortened the war by two to four years, and that without it the outcome of the war would have been uncertain.