"..... but of course it mustn't go any further! Careless talk costs lives."
A British WWII propaganda poster depicts two men in a train talking. Hitler and Goering sit above them in the luggage rack.
Cyril Kenneth Bird, known by his pseudonym Fougasse (a type of land mine), was an established British cartoonist by World War II. He was art editor of Punch magazine and later chief editor. During WWII, he worked for free for the United Kingdom's Ministry of Information, designing humorous propaganda posters such as the one seen here.