I've been talking to and emailing a few people about the lack of any good communal singing sessions at the National in recent years, and the upshot of it all is an unofficial arrangement to meet in the session bar at 3.00 pm each afternoon of the festival to see what develops.
Various themes have been explored in discussions, and there are a few things that seem to be agreed:
1. The "singing room" has lousy acoustics.
2. A lot of folkies (particularly some good singers) are getting old. They don't like three o'clock in the morning sessions any more.
3. We have to do it where people can see and hear it, so we can oick up new people. This can't be done where there is no passing trade.
4. We need hard walls and a comparatively low ceiling for good acoustics.
5. Desirable conventions (can't have "rules" in a singing session): songs must have at least a chorus; no yodelling; preferably unaccompanied; can't lead anything you've written yourself unless it is widely known and generally accepted.