Just to stir things up a bit, I reckon this bloke is tougher than either of the English ponces discussed in this thread.
http://www.survivorman.ca/
He doesn't have Gryll's "wonder-knife" and bottomless water bottle, nor does he have Mears' plush camper-van to retreat to at sun-down for some medium rare veal and a nice bottle of Chateauneuf de Pape.
No water. No tools. No camera crew. Ave it.