Commander (The Poison Sky)
A Sontaran Commander, distinguished by his rank insignia of three diamonds on his Sontaran space armour, served aboard the flagship of the Tenth Sontaran Battle Fleet in the attempted Sontaran invasion of Earth. After Commander Skorr was killed on Earth, this Sontaran appeared open-skinned. He operated controls as General Staal ordered the launch of clone pods in anticipation of Earth's conversion into a Sontaran breeding planet, only for the Sontarans' caesofine gas to be eliminated by the Tenth Doctor, and the flagship itself destroyed by Luke Rattigan. (TV: The Poison Sky [+]Loading...["The Poison Sky (TV story)"])
Behind the scenes
Curiously, this Commander's rank insignia is seen on the left side of his collar rather than the standard right; it appears that, for an indeterminate reason, the image of his brief appearance was horizontally flipped.
