In the scene where the UFO spotter finally encounters the mysterious craft, the radar "pings" are the exact notes and timing from the start of Pink Floyd's track "Echoes"
The drawing of the UFO's insignia is that of a flux capacitor.
This is the second episode that involves UFOs as part of the plot, the first being series 4 episode 3, The Electric Vendetta.
Pip Torrens plays Group Captain Jeremy Ford in this episode. He previously played the role of Fergal Jenner in episode 13.3, Blood on the Saddle (2010).
Alison Steadman plays Abigail, which is coincidentally the same name as the unseen character from the TV play Abigail's Party, in which Steadman famously appeared in 1977. Also, two other characters in the play were named Cooper. In this episode, the name of the village is Cooper Hill.