I suppose some of this is a "lost story" but I wrote about Delilah back in 2012: https://blog.jgc.org/2012/03/delilah-secure-speech-system.html https://blog.jgc

I suppose some of this is a "lost story" but I wrote about Delilah back in 2012: https://blog.jgc.org/2012/03/delilah-secure-speech-system.html https://blog.jgc.org/2012/03/delilah-secure-speech-system.ht... and the actual system is on display at Bletchley.