This song, with the title “Oxford City”, goes back at least 200 years, having been printed over and over again. Some folklorists have given the song the title “Jealousy”, which seems appropriate. It is a favourite with gypsy singers. American versions exist, even a bluegrass one “Little Glass of Wine”, recorded by the Stanley Brothers.
Williams did not collect a tune but for possible tunes to this song, go to ‘Browse’ and search for 218 in the Roud number search.