The thing that Ann (Gemma Jones) is checking upstairs in her medicine cabinet, when Morse is visiting for the second time, is an early home pregnancy test. Using it was quite a lot of work, and it had to stand undisturbed for two hours before the result showed. A tilted mirror in the transparent box let the user see the bottom of the test tube. If a dark ring showed there, the test would be positive.
Along with his signature Jaguar, Morse drives an Austin Rover Montego in several scenes.
Colin Dexter: Author of the Inspector Morse book series appears when Morse visits the rooms of Ned Murdoch at College. Morse walks past Colin Dexter walking the opposite direction, and after they pass each other, Morse turns around and looks back at Dexter as he is walking away.