This song was inspired by an air raid on London in the Spring of 1941. In Noël Coward: The Complete Lyrics
, which was published 25 years after his death, Coward says he was at a railway station where "Most of the glass in the roof had been blown out and there was dust in the air and the smell of burning."
People were undeterred, and this moved him to write a song that captured the spirit of the Blitz. It took him a couple of days to finish; he based it on "Won't You Buy My Sweet Blooming Lavender, There Are Sixteen Blue Bunches One Penny;" the melody of this song had been adapted for "Deutschland Ueber Alles" (the German National Anthem), he said, so "I considered that the time had come for us to have it back in London where it belonged."