This was all made just as the UK was negotiating to enter the EEC so I wonder if the writers had that in the back of their minds as the King of "Peladon" (David Troughton - following in his father's footsteps with the Time Lord) is greeting a diplomatic mission from the Galactic Federation that he thinks he might want to join. He's not of the strongest character, though, and it's really his High Priest "Hepesh" (Geoffrey Toone) who wants to rule the roost. Just by chance, the "Doctor" (Jon Pertwee) and "Jo" (Katy Manning) arrive and are mistaken for the delegates from Earth and she for a Prince...