The conversation between Gilmore and Rachel is similar to the one between the Brigadier and Liz in Spearhead from Space: Episode 1 (1970).
Sylvester McCoy ad-libbed The Doctor nicknaming Gilmore "Chunky". Simon Williams had this nickname in real life.
In the original script, Harry was killed by the Daleks. This was cut for time.
Allison Williams makes reference to "Bernard" and Dr Jensen mentions the British Rocket Group, referring to the TV character of Bernard Quatermass created by Nigel Kneale.
In a deleted scene, the Doctor cures Ace's leg injury.