...except that we are not sure it is a modern song, Edmund! When I first learned it in about 1974, my ex said.."oh, my grandmother used to chord that on the pump-organ!"

and look here

and here is an essay which seems to claim it came from " Paul Dehn's obscure little 1956 collection of essays and squibs, For Love and Money."

" One treasure in the Dehn book was his set of `Alternative Endings to an Unwritten Ballad', which introduced a new template character to the world of letters. Samples:

I stole through the dungeons, while everyone slept,
Till I came to the cage where the Monster was kept.
There, locked in the arms of a Giant Baboon,
Rigid and smiling, lay ... MRS RAVOON!"....

so....scholars bicker... *grin* (It is fun, though...once a year!)