Part 3 of the TV mystery Quiet As a Nun (1978), starring Maria Aitken as TV investigator Jemima Shore, who is investigating the death of Sister Miriam at her former convent school. Having been warned by one of the nuns that Sister Miriam was murdered, she is stunned when that nun then dies suddenly before she can question her further. But even more intriguing is the story she hears from the schoolgirls over dinner of the legend of the mysterious "Black Nun" who is said to only appear when someone is about to die. When she hears that one of the girls (Patsy Kensit) actually saw the ghostly figure before the latest death, she decides to investigate further, leading to her famous encounter with the Black Nun...
Also among the cast in this thriller are Renee Asherson, Brenda Bruce, Sylvia Coleridge, Doran Godwin, Margaret D'Arcy, Linda Slater, Sarah Webb, Michele Winstanley and a young Patsy Kensit in a important role. Apologies for the picture quality, by the way, but this is from an old video recording.