Shaffer adapted the play for a 1977 film starring Richard Burton, Peter Firth, Eileen Atkins, Colin Blakely, Joan Plowright, and Jenny Agutter, directed by Sidney Lumet.
Comparing the film to the play, English Professor James M. Welsh felt using real horses in the film was understandable, but argued the outdoor scenes infringed on the "abstract theatrical design" that gave the play its creativity [REF].