"MacColl was my favourite singer and I very much admired his theories on traditional song and how it should be performed."

I find the above a little hard to understand. MacColl's theories on how traditional song should be performed ?

One of the most interesting things about traditional music as far as I am concerned is the amazing diversity of style and delivery, variation of lyrics and tune etc. I didn't know there was a formula, what a pity Ewan wasn't around to teach Jeannie Robertson, Margaret Barry, Bascom Lunsford, Leadbelly, Aunt Molly Jackson, Walter Pardon, Tommy Jarrell etc etc.