Jack Campin asked: "The tune is the same as "My Old Man's a Dustman" - is there an original behind both of them?"
They're similar tunes, but here's what John Watt had to say about it (quoted in this Mudcat thread ):
" The tune by the way isn't mine. It is in fact a mixture of "Maggie Cockabendie" and Woody Guthrie's "Grand Rancoolie Dam" [sic!]. I steal all my tunes. Although it's in at least three books that I know of, people still get the words wrong!"