In one of the classrooms, Ace picks up a book on the French Revolution just as Susan had in An Unearthly Child (1963); Sophie Aldred studied the original to try to mimic Carole Ann Ford's stature.
The subplot involving racism and fascism in Britain was inspired by Terry Nation's basing the Daleks on the Nazis.
The military personnel are reminiscent of the UNIT regulars. Group Captain Gilmore is the Brigadier (the Doctor even mistakenly calls him Brigadier), Rachel Jensen is Liz Shaw, Allison is Jo Grant, and Sergeant Mike Smith is a mixture of Captain Yates and Sergeant Benton.
Ben Aaronovitch considered making use of other elements of Dalek continuity - including the Thals and the Ogrons - but eventually rejected these for fear of overcomplicating the story.
This is the first instance of a "skeleton effect" caused by Dalek weapons. This effect would be used in every subsequent Dalek story.