Level 5 planet
From Tardis Wiki, the free Doctor Who reference
A Level 5 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. Level 5 planets were protected by various Galactic Laws. (TV: Smith and Jones, Partners in Crime, The Eleventh Hour)
Earth, as of 1979, (TV: City of Death) 2008, (TV: Voyage of the Damned, Revenge of the Slitheen, The Eleventh Hour) 2009 (TV: Partners in Crime) and 2040, (AUDIO: Phantoms of the Deep) was a Level 5 planet.
