Some were even more ironic:
"22 April; deciphered 19 May"
The U boat campaign makes it necessary to restrict severely the reading of signals by unauthorised persons.
Once again I forbid all authorities who have not express orders from the operations division or the Admiral commanding U boats to tune in on the operational U boat wave.
I shall in future consider all transgressions of this order as a criminal act endangering national security.
Weeks-old material still had value in building up a knowledge of the system, but of course it was of desperate importance that the time-lag be reduced.
By the end of May 1941 they were able to bring down the time to as little as a day.
One message that was deciphered within a week read:
"19 May; deciphered 25 May"
From: Admiral commanding U boats
To: U 94 and U 556