Adapted from "The Kingston File", a ninety-minute radio play written by Stephen Gallagher for BBC Radio 4 in 1987.
Originally written by Stephen Gallagher to be the pilot episode for the anthology series "Chiller" in further collaboration with Lawrence Gordon Clark, director of the BBC's Ghost Stories for Christmas, most of which were adaptations from the work of M R James. Chillers achieved high ratings with its debut episode, "Prophecy" but fell victim to the scheduling practice of postponing episodes to make way for sports fixtures.