In this adaptation of what was reputedly Agatha Christie's favourite among her own novels, a scientist (Sutherland) turns up with evidence which would have cleared a tried murderer. Alas, the boy has been hanged, and the family seems more interested in covering up the past than rehabilitating his reputation. Set in the '50s, the film succeeds admirably in catching a feeling of repression and social conformity, and the idea of murder as a means of maintaining respectability rather than for gain or passion. Agatha Christie's creation is finally recovered from Cluedo territory, and provides British cinema with a genuine '50s black thriller. CPea.