Article 57 of the Shadow Proclamation

Article 57 of the Shadow Proclamation was a subsection of the Shadow Proclamation. This article prohibited the destruction of a fully established Level 5 planet such as the Earth if no hostility actions were implemented by the planet.

The Eleventh Doctor ordered the Atraxi to return to Earth after they decided the destruction of the planet in order to kill Prisoner Zero referring to this article. (TV: The Eleventh Hour).