Grey was a soldier under the command of General Carrington who acted as the general's radioman.
He helped the General captrue Mars Probe 7, but he and the General were pinned onto Bessie by the Third Doctor, allowing the Doctor to take the Mars Probe to Space Control. (TV: The Ambassadors of Death)
Behind the scenes
Grey is never named in on-screen dialogue; he is only named in the closing credits.
