It was one of the really early ones, when the Federation was big and powerful and really sick: Servalan was just the rash it had come out in. They used to do all this creepy stuff, where faceless Federation scientists in huge ugly but strangely compelling concrete Universities of East Anglia would poke about inside people's heads creating false memories and making them do stuff they would otherwise have been disinclined to. That's the kind of episode that wasn't made here.
See? Ominous things in ominous boxes so ominous women in ominous masks can implant new forms of the old slavery.