Milford wrote his surprisingly large-scale Flute Sonata in 1944, and this arrangement of the slow movement was made sometime between then and May 1951 when Gerald Finzi had what he called ‘a flute afternoon’. This was in fact a session reading through submitted scores, and Finzi mentions in a letter to Milford that the
Interlude was the only work those present wanted to do with the Newbury String Players, and so presumably it was first performed later the same year.
from notes by Lewis Foreman © 2004