Servalan
Fictional character from Blake's 7. Played by Jacqueline Pearce.
Servalan is the main recurring villain for the series. She is the Supreme Commander of the Galactic Federation, and a ruthless, fascist tyrant as well as a cold-blooded murderer. She owes her position to her own cunning, ambition and privilege, and wields power directly, rather than deriving it from any higher-ranking male.
She's absolutely fabulous.