Operational Impacts of Ultra on the Air War?

[Nick Beale]

One answer is (if you have the chance!) to read the original messages and check out all the ones with ZZZZ or ZZZZZ in the heading. The number of Z's = the urgency of the message. Broadly, ZZZZ = something that's happening now, while ZZZZZ = something that's going to happen. You could then follow up to see what the Allies did next.

The value of the majority of the messages though seems to lie in filling in the picture of the enemy's strength, dispositions and so on, or in showing what he was trying to achieve. That obviously informed Allied actions but it's much harder to say that "German message A led to Allied action B."

I've written before that the messages don't mean much if you cherry pick one here and another there. They convey more if you take them in bulk. For instance the ones after the Allies cross the Rhine add up to a vivid picture of the Luftwaffe's organisation falling to pieces.