Alex Campbell

David Alexander Campbell, (AUDIO: An Earthly Child) also known as Alex, was the son of David and Susan Campbell and great-grandson of the Doctor.

Early life
Alex was the only biological child of Susan and David Campbell. He was born ten years after the end of the 22nd century Dalek occupation of Earth. Susan and David did not tell him about his true heritage, as they believed it would make it hard for him to live his life on Earth. (AUDIO: An Earthly Child) Nonetheless, the news of Alex's birth was relayed by Susan to the Eighth Doctor via Hypercube. (PROSE: Ghost of Christmas Past)

Meeting the Doctor
After his father's death, Alex grew rebellious. He joined youth groups opposed to the new Earth Council. At age 17 in 2187, he met his great-grandfather for the first time while he was in his eighth incarnation. His great-grandfather saved him from the Guldreasi and told him of his origins. The Doctor wanted Alex to have an education on Gallifrey so that he could fulfil his full academic potential as a Time Lord. However, Alex saw Earth as his home and decided to stay with his mother. (AUDIO: An Earthly Child)

Six months later, Alex had Christmas dinner in the TARDIS with his mother, the Doctor, and Lucie Miller. Although the Doctor was his great-grandfather, he came to refer to him simply as "Granddad." During this visit, the Doctor analysed Alex's DNA and discovered that Gallifreyan genes constituted only 7% of his genome. Unlike full-blooded Time Lords, he was not telepathic and could not regenerate. The Doctor intended to give the TARDIS to Alex at some point, though only after he had travelled with him, even arranging a room for him. However, Alex decided to go on a grand tour of Europe with Lucie instead. (AUDIO: Relative Dimensions)

Fighting the Daleks and death
During the Daleks' second attempt to conquer Earth, Alex fronted a resistance with Lucie and saved the Doctor from being blown up in a Dalek saucer. (AUDIO: Lucie Miller) Alex and Lucie travelled in a Dalek saucer to the Dalek base in North America with a bomb to destroy them. The saucer was caught in a magnetrap, and Alex and Susan were taken from the saucer. However, he ran at the clamp's control panel and was shot by a Dalek, destroying the controls but killing Alex. (AUDIO: To the Death)

Alternative timelines
The Dalek Time Strategist found another version of Alex in another universe and captured him, placing him in a cryogenic casket and attempting to use him to manipulate the Eighth Doctor. The Doctor later acquired the casket and revived him, (AUDIO: Restoration of the Daleks) travelling with him and Cass Fermazzi whilst Bliss disappeared as a result of changes to the timeline. (AUDIO: Meanwhile Elsewhere, Vespertine, Previously, Next Time)

Physiology
Unlike his mother, as a Gallifreyan/human hybrid, Alex Campbell had one heart (AUDIO: An Earthly Child) and no telepathic or regenerative faculties; only 7% of his genome was Gallifreyan. (AUDIO: Relative Dimensions) The other 93% was human. (AUDIO: The Uncertain Shore)