This episode contains a rare instance of the series using video rather than film for location scenes. This came about because the location sequences in some of the earlier episodes this series (most notably "Hole in One (1985)") had been pre-filmed with Lennard Pearce prior to his death. When Buster Merryfield joined the show, the earlier episodes had to be re-filmed, which left them with only enough money to film half of the location sequences in this episode. The BBC agreed to cover the budget shortfall, but on the condition that video be used instead of film, due to its lower cost.
The idea for the script was based on a true story of a rare butterfly that John Sullivan had read about.