Equus

It's usually girls that have a fixation on horses, but this particular affliction also affects Peter Firth.

Sidney Lumet adds this version of Peter Schaffer's play to his list of memorable theatrical adaptations while Richard Burton earns his reputation breaching the third wall to provide the glue that holds the film together and was duly rewarded with several awards (including an Oscar nomination).

The orange-tinted scene in the barn where Jenny Agutter slips out of her jodhpurs and on to her back provides an unexpected thrill unfortunately blighted (SPOILER COMING:) by the truly shocking sight that immediately follows.