Basic thread? What if there wasn't one? I think that there was a mosaic, of lots of different things happening in different places. Some commercial, some not, some local, some national. The names that mean things to me would include Steeleye Span, Fairport Convention, Sandy Denny, but also the High Level Ranters, Johnny Handle, Bob Fox, from the North East, the Blackpool Taverners and Strawhead from the North West, Shirley Collins, Cyril Tawney, The Spinners, Jake Thackeray, The Corries, Ewan McColl and Peggy Seeger.

A single basic thread? No way.