This liner note taken from www. folkwise.cok.uk/cd/cd.html is interesting:

The Tommy Note.
Jon Raven's book "The urban and industrial songs of the Black
Country and Birmingham" suggests that this song is unique. It
is the only known song that describes the details of the canal
people's lives and it is the only song in the British industrial
song tradition to deal at length with the "truck" system. Given
the bitterness and resentment which most workers regarded
"truck" it is remarkable that no similar song has yet been
discovered. Jon Raven wrote the tune.