Gwyneth (The Unquiet Dead)

Gwyneth was a servant girl at Gabriel Sneed's home in Cardiff who had clairvoyant abilities.

Biography
Her parents died of influenza when she was twelve and she was brought up by Mr. Sneed. She fancied the butcher's boy.

When Gwyneth gave the Ninth Doctor a cup of tea, she said, "Two sugar, sir. Just as you like it", although she had never met him before. These psychic powers enabled her to be contacted by the gaseous Gelth who had arrived in the city via a space-time rift located there.

Gwyneth and the Doctor agreed to the Gelth's pleas to let them come through to Earth and possess dead bodies in order to survive. The Gelth lied to them about the extent of their numbers and their hostile intentions. When she stood underneath an archway in order to contact the Gelth, they passed through, and trapped the Doctor and Rose. To destroy them, she struck a match once the Doctor and Rose had escaped, igniting the gas in the chamber and destroying herself in the process. (DW: The Unquiet Dead)

Gwyneth's genetic traits would be passed, through the space-time rift via spatial genetic multiplicity, to her distant relative Gwen Cooper, an agent of the branch of the Torchwood Institute based in Cardiff in the 21st century. Gwen and Gwyneth looked practically identical, although Gwen did not inherit her psychic abilities. (DW: Journey's End)

Behind the scenes

 * Though Eve Myles played both Gwen and Gwyneth, Russell T Davies denied in a Doctor Who Magazine interview that they were in any way related. However he reversed this position in Journey's End by having the Tenth Doctor and Rose Tyler comment on the resemblance and the Doctor explaining it and Gwen saying her family had lived in Cardiff for centuries.