Sublime

The agents were using poems for their codes. Or famous quotations. Or anything they could easily remember. This concept of clandestine coding had been adopted by SOE because of a theory, traditional in Intelligence, that if an agent were caught and searched it was better security if his code were in his head. I had a gut feeling right from the star

Stuart Milner-Barry, one of the Hut 6 cryptanalysts, wrote: “I do not imagine that any war since classical times, if ever, has been fought in which one side read consistently the main military and naval intelligence of the other.”