The Dalek Supreme has a different paint job from the previous episode. The original paint job is visible in the reprise at the beginning of this episode.
The Dalek spaceship's main ramp has been repaired between episodes, despite the action being continuous.
William Hartnell flubs the line "you seem to place more reliance on that young man's word than mine".
When Dortmun wheels away from the table a shadow can be seen moving behind him even though he is supposed to be in the room alone.
London is supposedly deserted, but buses can be seen traveling in the background as the Daleks move through Trafalgar Square; and at 17:11 two humans are seen walking in the distance.