Faraday

Colonel Faraday was a UNIT officer around the mid 1970s.

Biography
Faraday was in charge of the Devesham Space Defence Station whilst Brigadier Lethbridge-Stewart was away in Geneva. Unbeknownst to him, the Kraals made an android duplicate of him, as well as Harry Sullivan.

When Faraday and Harry went to the XK-5 space freighter to meet up with Guy Crayford, they were captured by Styggron and replaced by their android replicas which the Doctor later deactivated.

The real Faraday and Harry were freed by Sarah Jane Smith, and subsequently witnessed Styggron's death from the Kraal virus after the Fourth Doctor turned the android replica of himself against the Kraal scientist. (TV: The Android Invasion)

During the Kraals' second attempted invasion of Earth in 1979, Faraday was in Switzerland. (AUDIO: The Oseidon Adventure)

Behind the scenes

 * The character of Colonel Faraday was created to replace the Brigadier, as Nicholas Courtney was committed to a theatre tour at the time and wasn't available.
 * Faraday has never been identified with a first name, either in The Android Invasion or any spin-off media.