Bletchley Park: Code-Breaking's Forgotten Heroes

Historical BBC documentary that depicts the work of codebreaker Gordon Welchman. During the Second World War, Welchman worked alongside Alan Turing at Bletchley Park, breaking German ciphers, and played a key role in cracking the Enigma machine. Following the war he moved to the United States and, after retiring, released a book detailing his work for both the US and UK military which led to him being ostracised by the National Security Agency.