Walton's Prologo e Fantasia, written at the end of his life, is one of the few completed original works of his final decade. Undoubtedly flawed, it can be seen simply as an exemplar of Walton's failing creative powers and his sheer difficulty in writing any music at all. But it is also possible to discern in it continued experimentation with developing aspects of his language, especially seen in the context of his exploration of similar devices in preceding works. Analysis of his harmony shows development of greater ambiguity in a tonal context. And, while many of his other works contain significant fugal passages, particularly towards their conclusions, the use of a fuga finta here presents a different perspective on a typical Waltonian device. While the work does not stand alongside Walton's most important orchestral achievements, and performances will probably remain relatively few, it does nevertheless provide some interesting insights into the musical language of his post-war music.