One of only two episodes of the entire series in which no extras featured; the other starred Richard Wilson alone.
This episode takes place entirely in the Meldrews' bedroom as Victor struggles to sleep, keeping Margaret awake. Victor and Margaret are the only characters present in this episode.
Takes place entirely in real time; this started the trend of one episode per subsequent seasons taking place in real time.
Margaret mentions Doctor Who (1963). Richard Wilson and Annette Crosbie would later appear in Doctor Who (2005) - Wilson in The Empty Child (2005)/The Doctor Dances (2005) and Crosbie in The Eleventh Hour (2010).