Grey (The Ambassadors of Death)

Grey was a soldier who acted as General George Carrington's aide and radio operator.

Biography
Grey was a "powerful-looking thick-set young man" with light, close-cropped hair and a heavy moustache. (PROSE: The Ambassadors of Death)

On General Carrington's orders, Grey sent a message to the aliens to bring them to Earth, after which he and Carrington captured Mars Probe 7. However, the Third Doctor held them up using Bessie and stole their vehicle, taking the craft to Space Control. (TV: The Ambassadors of Death)

Behind the scenes

 * Grey is never referred to by name in the on-screen dialogue; his name is given only on the closing titles of episodes one and two, as well as in Terrance Dicks's novelisation.