Sinister Supporter: of course a search for the origins of jazz leads to American folksong. And a search for the origins of that leads back to English folksong(among other things). Where is "the classic bit of folk misinformation" in that? It is true, and blindingly obviously true.

Why I'm dignifying this statement with a reply I don't know, but for the sake of a cultural truth long since misrepresented not just in the hallowed pages of TPBPOEFS but in the minds of those who have read it and believed it....

Jazz was created & developed by African-American musicians; the roots of the music are African, and the music remains primarily African-American. A search for the roots of Jazz leads you to Africa, not England. Jazz - Black Classical Music; Great Black Music - Ancient to the Future.

From WIKI: Jazz is a primarily American musical art form which originated at the beginning of the 20th century in African American communities in the Southern United States from a confluence of African and European music traditions. The style's West African pedigree is evident in its use of blue notes, improvisation, polyrhythms, syncopation, and the swung note.[1]

Note: blue notes, improvisation, polyrhythms, syncopation, and the swung note - not exactly your everyday fare in English Folk of any persuasion.