Just for the record the word 'hack' here does not mean an old weary horse. It is related to the slang word for journalists. It simply means lyricists at the bottom end of the literary world, some of them only temporarily. Some of our more celebrated poets have been known to try their hand in their early days when in need of a bob or two.

Don't forget also that a goodly portion of this material originated in the theatres and the pleasure gardens of London, before finding its way onto street lit. and then into oral tradition.