 The cantata involves at least two children's choirs, and incorporates two congregational hymns sung by the audience.Britten also used this fusion of professional with amateur forces in "The Little Sweep" (1949), which forms the second part of his entertainment for children, "Let's Make an Opera", that he devised with Crozier.Again, child singers (also doubling as actors) were used, and the audience sings choruses at appropriate points.