Tom, I think we're probably agreed that songs don't enter the tradition by the choice of their makers, but by widespread popular adoption (in a world of home-made entertainment that I argue doesn't exist in the same form any more). But what lies behind a lot of people's judgement (possibly including Jim's) of what is 'folk' and what isn't, is what it sounds like. This involves content rather than provenance: melody, text, style. Cyril Tawney's songs, although dealing with contemporary topics, sound at least a bit like Sharp-defined trad folk by virtue of their tunes and the way Cyril sang them. And of course he was a wonderful singer of trad songs, as well as his own.