From A. L. Lloyd's liner notes to Leviathan! Ballads and Songs of the Whaling Trade:
Early in the 19th century a whale skipper was charged in King's Lynn with the murder of an apprentice. A broadside ballad, in the form of a wordy gallows confession and good night, appeared, and in course of circulating round the East Anglian countryside it got pared down to the bone. The poet George Crabbe was interested in the case, and took it as a model for his verse-narrating of Peter Grimes which subsequently formed the base of Britten's opera. The opera is in three acts. The same ground is covered in three verses by a song as bleak and keen as a harpoon head.