Apted's biopic about the late Diane Fossey's mission to save the endangered mountain gorilla has, to some extent, been pre-empted by wildlife programmes on TV. This is not to denigrate Sigourney Weaver's committed performance, but to question the dramatic rigging around the humans. One of those spiky crusaders with tunnel vision, Fossey pitched herself on a wet, cold mountain in Rwanda, and set about her life's work. Her research cleared away a mass of misinformation about gorilla behaviour, and the scenes in which she gradually establishes a communication with the reclusive species are the real interest of the film. Her relationship with the photographer (Brown) who puts her cause on the map, initial hostility turning into love affair, feels like a box-office consideration; over the years, her battles with poachers and government officials distort her into a dangerous Messianic crank, but the transition here seems abrupt. Script problems apart, the film is too long, but the footage with the gorillas is always extraordinary.