H is for... Helen A

The tyrannical ruler of the planet Terra Alpha, which was home to an earth colony in the 24th Century. The planet had been inhabited by diminutive rodent-like humanoids called Alpidae prior to the arrival of the humans, but they had been forced to live underground. One of the planet's chief exports was a form of sugar. Helen A decreed that her colony would be the happiest in the galaxy, and that meant that all sadness and melancholy was banned. She set up all-female squads called the Happiness Patrols to enforce her totalitarian laws. Anyone found being sad was deemed a "Killjoy" and they were disposed of. Some were sent to the Forum to attend Happiness Patrol auditions. Those who failed were killed by her chief executioner, the sadistic robot Kandy Man. Some were killed at special holding areas, where there were lethal joke machines. Others were simply gunned down by the patrols. Helen A had spies everywhere. Even melancholy music and colours which suggested sadness - like blue - were banned. Helen A had as her consort a man named Joseph C, but his interest lay more with Gilbert M, the creator of the Kandy Man. Helen A instead lavished all her attention on a Stigorax named Fifi - a savage canine creature. The Doctor arrived on the planet one night after hearing of the rumours of mass disappearances in the colony, and he determined to bring about the end of Helen A's reign. After the Doctor had fomented a revolution against her, Helen A decided to flee the planet to start again somewhere else. However, as she was trying to leave she came across her dying pet and broke down in tears - learning too late that sadness and happiness couldn't exist without each other.

Played by: Sheila Hancock. Appearances: The Happiness Patrol (1988).

• Of course, Helen A was a thinly disguised version of then UK Prime Minister Margaret Thatcher, with Joseph C her husband Denis.
• Hancock is the widow of Inspector Morse actor John Thaw. In her autobiography she glosses over her appearance in Doctor Who.