Susan Foreman
Carole Ann Ford

Susan was the first ever on-screen companion of the Doctor and she stayed on Earth after the Dalek Invasion in the 22nd century. Susan is the granddaughter of the Time Lord known as the Doctor. Her last name of Foreman is an alias taken from the junkyard, owned by an "I. M. Foreman" at 76 Totter's Lane, where she and the Doctor lived (in the TARDIS) during their time in London in 1963.

The Doctor explains that he and Susan are exiles from their own people. Susan adds, "I was born in another time, another world".  Her age is given as 15.