Grierson

Grierson was a technician at the Space Defence Station in Devesham.

Biography
Grierson and Tessa monitored Guy Crayford's return to Earth.

He also assisted the Fourth Doctor in defeating the Kraal invasion, and was shot and wounded by the android duplicate of the Doctor. (TV: The Android Invasion)

Behind the scenes

 * A scene featuring Grierson was recorded for part one, but was edited out of the finished programme for timing reasons. Because this edit came late in the day, Dave Carter was still credited on-screen even though he did not appear. The missing scene was, however, reinstated for Terrance Dicks's novelisation of the story.