Stephen Lawhead says so. Our offices being in Nottingham, I thought it was only right to show this one. Apparently, he didn't hide in Sherwood, but somewhere in Wales.
"In short, then, Lawhead's point is that Robin and his fellow outlaws could not have escaped the Sheriff of Nottingham for long if they had lived in a nice little woodland picnic spot, with lots of space between the trees."
Although, as Lawhead says, "I've got a long-term fascination with all things Celtic, and particularly Welsh." He adds, "Look, I'm a fantasy writer first and foremost, not a historian."
So there you have it.