PIPE PERSONS / PIPE PEOPLE

Planet of Origin: Terra Alpha (human designation), am Earth size planet with a yellow-purplish atmosphere.

The Pipe People are 4 feet tall humanoids which developed a preindustrial civilisation. They were forced to live underground when humans colonised their planet. They assisted the human working class in a rebellion against the colonial regime which led to a subsequent peaceful cohabitation.
Source: Doctor Who Universe, (DW: The Happiness Patrol)