In terms of the English and I mean English finding and being pointed in the direction of their own song tradition the most important person standing at the turning point was Lonnie Donegan (in this I agree with Bert in a posting in 1999)

I have just heard a Radio 4 prog with Shirley Collins and her folk song association with Alan Lomax (I have also been present at a workshop she gave a couple of years ago) and give great credit to all the folk song collectors, without whom artists of the ilk of Martin Carthy, Tony Rose, Dave Burland, Nic Jones, Derek Brimstone, Martin Whyndam-Read, Peter Bellamy et al would have been hard pressed to find material
Most significant folkie Lonnie Donnegan (followed by William Appleby) remember him)
I remember sitting in my junior school listening to the radio in Barnsley singing 'and shall Trelawney live and shall Trelawney die here's 20,000 Cornish men shall know the reason why'

Many Sat mornings listening to Lonnie Donnegan and Rock Island line and the rest