Nine years down the line............Here are a few vids of a massed choir sing at Sheffield 2010.
Thought I would share these youtube vids with you as they don't seem to fit in with the youtube folk music permathread categories(being choir) but I reckon its kinda contempory folky; and seeing as I was part of it anyway............and maybe Bagpuss was there too!

http://www.youtube.com/watch?v=-KklWkhG748 Nana was a suffragette
http://www.youtube.com/watch?v=oq0i6nFRlWw&feature=related Rosa Parks
http://www.youtube.com/watch?v=ACDUY-kXF08&feature=related Unison in Harmony
http://www.youtube.com/watch?v=kodCq8rL9Uw&feature=related Gentle Happy People/Singing for our lives