G is for... Gwendoline

Gwendoline was the young ward of a man named Josiah Smith, who lived in a house called Gabriel Chase in Perivale, in 1883. The house had belonged to her father, who she claimed had gone to Java. She befriended Ace when she and the Doctor arrived in the house. Ace had set fire to Gabriel Chase in her time, having sensed great evil there. The Doctor wanted her to see the nature of that evil.
Smith was really an alien who was evolving into a human being, part of an experiment by another alien known as Light. He wanted to become the ultimate human being - the head of the British Empire - and was working on a scheme to assassinate Queen Victoria.
Smith had twisted Gwendoline's mind, along with others in the household. "Going to Java" was a euphemism for being killed, as Smith had murdered her father with her collusion. The housekeeper - Mrs Pritchard - was really Gwendoline's mother, their memories blocked by Smith. Gwendoline later turned on Ace and tried to kill her and the Doctor. When Light was released from hibernation, Gwendoline and Mrs Pritchard finally remembered who they were after seeing a photograph in a locket. Their reunion was cut short when Light turned them both to stone, to stop them from evolving and spoiling his catalogue of Earth species.

Played by: Katharine Schlesinger. Appearances: Ghost Light (1989).

• Katharine's name was misspelled as 'Katherine' on the first two episodes as broadcast, as well as in the Radio Times billings. It was corrected for the final part, and for the story's subsequent VHS and DVD releases.