Inspired by the enlightened tuition of Douglas Lilburn at the early Cambridge Summer Music Schools, Pruden entered the London Guildhall School of Music and Drama (1951–54) where he developed timpani and conducting skills, and undertook a concentrated training in composition under Benjamin Frankel. A highly professional craftsman, Frankel believed in a keenly developed ear rather than theoretical preoccupations and, according to Pruden's extant lecture notes, his golden rule was "to fabricate with the thread of melodic invention, not the rope of rhythmic twisting."

Capriccio, begun as an early exercise for Frankel, marks a new stylistic poise in Pruden's writing. There is plenty of spirit and character in the piece; the music pivots on a mercurial motif which plaits through a beguiling second theme, and these ideas are enlivened by cross-rhythms and bitonal play.