Nice to see an intelligent discussion on this, but how long will the horse brigade stay away?

I suggest that the point about "popular" was that it was the most likely source of taint, and that rather than simply deleting that word, it should be replaced by the words and symbols "popular (or other)"

Much jazz would I think fail branch (i) of the 1954 definition but "trad" jazz would get within it and IMHO rightly so since it is the "folk" music of a particular part of the community. The borderline could get a bit iffy though!

This particular form of the definition does not require that the work should be of no known authorship, and so long as the other branches of the test are satisfied that might be a good idea and resolve part of the argument with the ARSS tribe.

The consequence would be that (for example) "Fiddlers Green" and "Ride On" would then be "folk".