Colin Frazer

Colin Frazer was the cousin of Tegan Jovanka. While vacationing with his friend Robin Stuart, they arrived a day early in Amsterdam in 1983 and could find no empty hotel room. They decided to spend a night in the abandoned Frankendael mansions. Colin was abducted by the Ergon and forced to help Omega return to corporeal existence. He was later freed by the Fifth Doctor. (DW: Arc of Infinity)

It is unknown if he is the nephew of Tegan's aunt Vanessa (DW: Logopolis) or the grandson of her maternal grandfather Andrew Verney (DW: The Awakening).