This was the last Doctor Who serial to use 16mm film for scenes on location instead of video. It was a practice that had been in place since The Reign of Terror in 1964 and was common in many other British television productions, although it had been falling out of favour since the start of the 1980s.
Eric Saward kept The Doctor to a minimum in this story, instead writing extensively for the supporting characters. He later revealed in interviews that he thought Colin Baker had been miscast as The Doctor. Pip Baker and Jane Baker later commented that Saward's treatment of The Doctor in this story was a sign of how all was not well behind the scenes on Doctor Who at the time.
The Glass Dalek was an idea that Terry Nation considered for The Daleks, but was omitted for being too expensive.
Eric Saward thought up the idea of blue 'mourning' suits for Necros in order to cover up Colin Baker's costume, which he considered inappropriate for a drama series, for as long as possible.
The idea of turning the dead into a food source is reminiscent of Soylent Green (1973). Eric Saward admitted that he hadn't seen the film before writing the serial.