Not only did the British have the Enigma machine coded messages largely broken, they had another rather clever way of divining German information.

All captured German flying personnel were housed together in a large mansion in sort of a communal manner.  They were free to mingle during the day, visit each other’s detention rooms, and commingle as they wished.

The English had the entire place wired for sound, with recording, listening and transcription occurring in the basement.  The captives would talk among themselves, revealing German weaknesses, plans, strengths as well as their opinion of the English.  They were surprised that the English had as many airplanes as it did, for instance.

I happen to think that was about as clever as can be.  It may not have an immediate, tactical effect but certainly knowing what the morale, attitude and knowledge the front-line flying people was certainly had to help.