This episode overran its 25 minute limit and rather than cut material out, the cliffhanger was changed from Davros' speech to the Doctor being electrocuted.
Sarah was originally going to contract radiation poisoning, recalling a similar story strand in The Daleks.
This episode was watched by 8.5 million viewers on its original transmission.
Guy Siner who plays Ravon and Hillary Minister who plays a Thal Solider would later appear together in Allo Allo, although they share no scenes here.