The Spanish Link in Cracking the Enigma Code

This morning, BBC Radio 4’s Today programme broadcast a short report by Gordon Corera on the presentation of two German Enigma code machines by the Spanish Army Museum in Toledo to GCHQ, the British signals intelligence agency. GCHQ will retain one of the machines and the other will go to the museum at Bletchley Park, Britain’s World War II code-breaking centre. The Spanish Army Museum received a later and more sophisticated machine in return. An NCO found several Enigma machines in the Spanish Defence Ministry a few years ago.

Germany and Italy both sent forces to support the Nationalists in the Spanish Civil War. The Germans used Enigma machines to ensure that their communications were secure. Britain was aware of the Enigma machine and in 1927 bought a commercial version, which was less sophisticated than the military one. German military radio traffic could not be heard in Britain, but Britain could detect the radio signals of the Germans in Spain, enabling work to start work on decoding the Enigma.

The main benefit of these efforts were that they showed the British that the Enigma code was not unbreakable. The Poles, who could pick up German military radio signals, had made more progress in breaking the military Enigma code and shared these with Britain and France just before the start of the war.

The story of the successful efforts to break the Enigma code during World War II  is now well known, although the Polish contribution is sometimes underplayed. The manner in which the foundation to these attempts was laid during the Spanish Civil War was unknown until now.

Gordon Corera wrote an article on the story for the BBC’s website. It emphasises the importance of technology and co-operation between countries in intelligence and security. This link to the BBC website includes his report; not sure if it will work outside the UK. (Warning! It starts as soon as the page opens.) He interviewed GCHQ’s official historian, who was introduced as being called just Tony. Apparently, GCHQ is so secret that the surname of its historian cannot be revealed!