During World War II, Winston Churchill referred to Ultra — the information coming from the previously unbreakable German Enigma machines (among many other ciphers and systems including Lorenz) — as his “special intelligence”.
Bletchley Park was home to the central site for Allied codebreaking. If the Germans knew their communications were being intercepted, the war could have gone on for months and even years.
“My own conclusion,” said Sir Harry Hinsley, Bletchley Park Cryptanalyst and author of “British Intelligence in the Second World War”, “is that it shortened the war by not less than two years and probably by four years — that is the war in the Atlantic, the Mediterranean and Europe.”
Today, Bletchley Park is a tourist attraction.