Johnny, for this discussion to be useful (and I think it's a really interesting one), we need to ...

1. define 'middle class' and 'working class'. Are these meaningful terms any more? Arthur Scargill said (and I certainly wouldn't agree with everything he said) that working class means anyone who has to work for a living, anyone who doesn't own the means of production. That's almost everyone. It certainly includes teachers and lecturers, and is not based on culture ('middle class culture', 'working class culture') or income (as such). Some of us used to define a 'working class' person as one working in industries which barely exist any more or are actually extinct in the west.

2. show that folk clubs are exclusively or predominantly populated by the middle class. Impossible, I'd say, working on the definition above. Who has done such a survey? When and where? What definitions were in use?

3. show that somehow the 'middle class' are 'to blame' for excluding the 'working class'. If the so-called 'working class' are absent by choice, because they'd rather be listening to something else, there's not much the rest of us can do about it. The 'working class culture' that gave rise to the spread of these songs has been dead a long time.