I think there's a thread on it somewhere. There is actually a full book on it by I think Arthur Kellett. Apparently it dates from the 1920s among ramblers from the big cities. I've known it practically all my life, being a Yorkshireman, but I don't think it would stand up to the variation factor. It certainly started off in a specific community and then was taken up as some sort of Yorkshire anthem, so then a wider community; much like the broadside ballads actually.