"Don't Let's Be Beastly To The Germans" was a satirical, patriotic song popular in Britain in World War II. It was composed by Noël Coward. Although popular when performed live (British Prime Minister Winston Churchill himself demanded several encores when he first heard it) the humour did not translate well over the wireless and caused some fuss, leading the BBC to ban the song.
The refrain is:
References
Don't Let's Be Beastly to the Germans Wikipedia(Text) CC BY-SA