This series of supernatural dramas from the early 1980s is the sort of thing that could very easily be parodied – has been parodied, in fact, by everyone from Victoria Wood and French and Saunders to The League of Gentlemen and Garth Merenghi's Darkplace. Every shonky visual effect, every discordant stab of strings as the camera's point of view creeps up behind a character, every window that blows open extinguishing a candle: these are meat and potatoes to sketch writers, and this makes it hard to watch these episodes with a straight face... at first.