Interplanetary war
An interplanetary war was a war fought between planets, examples including the Human-Draconian War, the Second Dalek War, and the Third Dalek War. (PROSE: The Chase [+]Loading...["The Chase (novelisation)"])
By the time he first battled the Third Doctor, the Master was already responsible for several Interplanetary Wars. (PROSE: Doctor Who and the Terror of the Autons [+]Loading...["Doctor Who and the Terror of the Autons (novelisation)"])
In 2006, Earth's first interplanetary war was anticipated as the British government requested that the United Nations provide access codes for nuclear weapons against an alien threat. In reality, this was a Slitheen plot to destroy the Earth for profit, which was thwarted by the Ninth Doctor. (TV: World War Three [+]Loading...["World War Three (TV story)"]) Mickey mentioned that the interplanetary war was more "freaky" than simply moving on and forgetting. (PROSE: Hoax This! [+]Loading...["Hoax This! (short story)",""]
Over the fifty years following sending a rocket to Mechanus, Earth became involved in interplanetary wars which put an end to Earth's expansionist phase, leaving planets like Mechanus uncolonised. (PROSE: The Chase [+]Loading...["The Chase (novelisation)"])