Level 4 planet

A Level 4 planet was a designation used by Galactic Law in reference to certain worlds, with the implication that it referred to relatively primitive planets not yet fully integrated into galactic civilisation. Other designations included Levels 1, 2, 5 and 6.

The Jariden Colonel Ulrik described 19th century Earth as possessing sub-Level 4 technology. (AUDIO: The Four Doctors)

Romana I once referred to Earth in 2011 as having a level 4 civilisation, (AUDIO: Ferril's Folly) despite other sources designating it as a level 5 planet from the late 20th century (PROSE: First Frontier, TV: City of Death) and into the 21st century. (TV: Revenge of the Slitheen, Voyage of the Damned, Partners in Crime, The Eleventh Hour, AUDIO: Phantoms of the Deep)

River Song, in the spaceship Sarah Jane, once lured a SporeShip away from a inhabited level 4 world. (AUDIO: The Rulers of the Universe)

The Quiet One's home planet was a level 4 society. (AUDIO: Shadow of Death)