One name that seems to have been missed from many British Catters is the name Pete Coe. He has had great deal of influence on many people and has done a great deal to encourage youngsters to become involved in song, dance and music.
Martin Carthy has been mentioned by many and I cannot disagree with his name being put forward either.
How about people like Fred Jordan.He was very significant and so were many others who kept singing the songs of their fathers and grandfathers, without them the collectors, Cecil Sharpe and all would not have had anything to collect.
Being from the UK my ideas of significant are biased towards those names that I know,others from other countries will be similarly biased, but their suggestions are no more valid nor no less valid than mine.
I think that all of us who enjoy "Folk Music" should thank all of those people named in this thread for the contributions that they have made to our kind of music.