D is for... Delta

A Queen of the Chimeron race, who were being hunted to extinction by the Bannermen. She fled with a single egg - that of a Princess - and made her way to a Space Toll Port. Here she swapped ships - taking the Doctor's place on a Nostalgia Tours flight to mid-20th Century Earth. The Bannermen, led by General Gavrok, gave chase. Delta found herself the object of romantic interest by a young man named Billy, who worked at the Shangri-La holiday camp where the tour flight crash-landed. She was sharing a chalet with the Doctor's companion Mel, who witnessed the birth of the Chimeron Princess. It rapidly grew into a girl, then into a teenager, thanks to a special nutrient which Delta fed to her. Unbeknownst to her, Billy had taken some of this food, and used it to transform himself into a human-Chimeron hybrid. After the Doctor had defeated the Bannermen, and their leader had been killed, Delta and Billy left Earth with the Princess and the Bannermen prisoners, determined to seek legal redress for the persecution of her people, and to begin rebuilding the race with Billy.

Played by: Belinda Mayne. Appearances: Delta and the Bannermen (1987).