Jeza, now that you mention it I see they have it down as a Donovan song. He was OK, Mellow Yellow and the like, but I never thought he would have written something as powerful as that.
Tamborine, I'd always associated Big Bill Broonzy with that particular song. I live and learn.
Hexagone by Renaud I notice is on there to my surprise and delight.
If I was to add my own:
"Shirt of Blue" by The Men They Couldn't Hang (about the Miners' strike)
"Birmingham Six" by The Pogues (about as angry as it gets)
and probably "Miss Maggie" by that man Renaud again (about you know who, and with a sublime last verse :-)