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.