In the original script, the Doctor defined the Time Lords as being the leaders of his race.
It was David Maloney who came up with the sequence in which the Doctor sends his plea to the Time Lords in a small box.
At 9 episodes David Savile (Lieutenant Carstairs) appears in more episodes as a single character than some companions, beating out Katerina (5 episodes) and Sarah Kingdom (9 episodes)
This episode was watched by 4.1 million viewers on its original transmission.