GalSec

Galsec was a human colony, descendent from a colony ship sent out by the Earth around the time of the Expansion. During the following 10,000 years they established an Empire with bases across the Galaxy. At some point the Sontarans lured a group of GalSec soldiers to Earth with a fake distress signal in order to test their fighting capabilities. (DW: The Sontaran Experiment)