Tish Jones

Letitia "Tish" Jones is the daughter of Francine Jones and Clive Jones, the older sister of Martha Jones and Leo Jones, and the aunt of Keisha Jones. She was also cousin of the late Adeola Oshodi.

Tish witnessed the Royal Hope Hospital disappear, and later attended her brother's birthday party. (DW: Smith and Jones)

She then became the head of PR for Richard Lazarus, who made himself look 40 years younger. After the experiment he seduced Tish on the roof of his lab where he turned into a monster that tried to kill her.

Fortunately Martha and the Doctor arrived in time to save her. After everyone had evacuated the lab, he escaped to a cathedral where he chased Martha and Tish to the top of the tower and tried to kill them but the Doctor saved them by killing the mutated form of Lazarus with soundwaves. (DW: The Lazarus Experiment)

She then began to work for Harold Saxon when he became Prime Minister. The fact was he only hired her so that he could get to Martha when he arrested her that caused Martha to come to the Valiant to release her family her family. But Martha was unsuccessful.

A year later Tish was working on the Valiant as a slave with her mum and dad. She and her family tried to break out and stop the Master but they failed at each attemped. Martha was captured by the master. Just as she was about to be shot the Doctor de-aged because everyone said his name.

And the Doctor reversed the Paradox machine setting everything back to 2008. She, her mum and dad still remember everything from the future that was destroyed so they know the Doctor's real identity. (DW: The Sound of Drums / Last of the Time Lords)

Alternate Timeline
She was on TV when the Royal Hope vanished to the moon on Donna's parallel world. (DW: Turn Left)