Andrew Graham-Dixon explores the ancient Christian practice of preserving holy relics and the largely forgotten art form that went with it, the reliquary. Fragments of bone or fabric placed inside a bejewelled shrine, a sculpted golden head or even a life-sized silver hand were, and still are, objects of religious devotion believed to have the power to work miracles. The documentary features interviews with art historian Sister Wendy Beckett and Neil MacGregor, director of the British Museum.

• Documentary