The scene where the Doctor soothes Aggedor was to feature the Doctor intoning the Tibetan chant "Om mane padme hum", but it was decided to instead use an expanded version of the Venusian nursery rhyme "Kokleda partha mennin klatch" introduced in The Daemons at the end of the previous season. Jon Pertwee sang this to the tune of God Rest Ye Merry Gentlemen.
This episode was watched by 7.8 million viewers on its original transmission.
This episode takes place on Peladon in 3885.