It was certainly the received wisdom at the time. I can recall in my youth aged, well-oiled cockney relatives bursting into wartime songs at family functions.
One I remember was to the tune of battle Hymn of the Republic (Glory glory allelluila (sp?)). Two of the verses were:
"The Yanks were flying Fortresses at forty fousand feet (x3)
With loads of ammunition and a teeny-weeny bomb"
followed rapidly by:
"The RAF were flying Lancasters at zero-zero feet (x3)
With no ammunition and a
great bomb!"
