To the South London teenagers Rock ‘n’ Roll is something quite mysterious, and different from the old jazz. But to the jazz experts its pedigree is dull and not very respectable. Rock ‘n’ Roll, it seems, is a rough mongrel of blues and hill-billy, with some hot-gospelling thrown in. It’s novelty isn’t so much in its beat or tunes, as in the raucous, jungly accompaniment of a honking saxophone and crude guitar-strumming, and a very powerful beat. The result is a naked, aggressive kind of jazz which most jazz pundits despise.