That album Dave Van Ronk first did Green Green Rocky Road on, also had a trad jazz band.

The reason you Americans find it so difficult to understand why us Brits are so precious about our traditional music, is that we have a style of traditional music that (though adhered to passionately by a middle class minority) totally alienates the general population. As somebody remarked to me in folk club last night, Traditional English music is an acquired taste - and hardly anybody bothers acquiring it.

Our 'traditional' music is generally reckoned to be under threat of disappearing if its adherents look the other way, take their eye off the ball.

Jazz like blues (though it has been quite popular with most English people for quite a while) is thought to be a corrupting influence.

Mention of Lennie Tristano reminded me that I once saw Davy Graham (inventor of DADGAD tuning - can't get more traddie than that) play an instrumental homage he had written himself to this great musician. So not every English folk musician gets the vapours and goes No No No No, at the very thought of jazz invading the holy of holys - English folk music.