Life as a television priest has never been more exciting. In this new three-part thriller (23 September), Anna Maxwell Martin plays the Revd Merrily Watkins, a young vicar being trained in “deliverance ministry”: exorcism, in other words.“Your job,” said the tutor, Huw Owen (David Threlfall), in the opening episode, “is to protect people from the intrusion into their lives of entities which half the professed Christians in this country don’t believe in.” With that he took his trainees into the kitchen and invited them to detect the chill in the air that bore witness to “an imprint” of a long-dead inhabitant. Watkins felt it, though she confided to Owen that she only took the job because “female diocesan exorcist sounded quite coo