Ultimate Sanction

Proposed by Lord President Rassilon as the last resort to winning the Last Great Time War, the Ultimate Sanction involved the creation of a paradox so severe that the resulting spatial-temporal rupture would rip the Time Vortex apart.

As this would be a suicidal measure, Rassilon devised a way of allowing the Time Lords to escape the disintegration of Creation by having the whole race shed their corporeal bodies and become creatures of consciousness alone, ones that would escape the effects of time and of cause and effect.

Rassilon nearly succeeded when his sleeper agent,, used a Whitepoint Star diamond to send a physical rhythmic signal of four beats into time and space. Rassilon locked onto that signal. He used it as a homing beacon to break Gallifrey and every participant of the Last Great Time War out of the time lock and begin the End of Time.

Rassilon's plan was again foiled when the Tenth Doctor used Wilfred Mott's old service revolver to destroy the diamond. Rassilon tried to kill the Doctor for this, but was attacked by the Master, saving the Doctor. The Master assaulted the Time Lords as Gallifrey was plunged back into its last day. (TV: The End of Time)

News of the Ultimate Sanction, or at least that the High Council was planning something, was brought to the General by Androgar, but the General dismissed the Council's plans as having "already failed". Later, the first thirteen incarnations of the Doctor saved Gallifrey in a pocket universe. (TV: The Day of the Doctor)

This event was foreseen by the Ood (TV: Planet of the Ood), Carmen (TV: Planet of the Dead), the Trickster (TV: The Wedding of Sarah Jane Smith) and apparently even Lord Azlok of the Viperox. (TV: Dreamland) They all tried to warn the Doctor through prophecies, which also informed him of his upcoming regeneration.

When the Twelfth Doctor returned to Gallifrey, Ohila of the Sisterhood of Karn said that the Doctor blamed Rassilon alone for the horrors of the Last Great Time War, presumably including this. When faced with Rassilon for the first time since Rassilon attempted the Ultimate Sanction, the Doctor ordered him to "get off my planet" and all of Rassilon's immoral actions caused the military to back the Doctor and banish him for his war crimes. The Doctor also banished the High Council for the same reason. (TV: Hell Bent)

Behind the scenes

 * Rassilon planned for the Time Lords to escape the effects of the Ultimate Sanction by becoming "creatures of consciousness alone". This is exactly what the Celestial Intervention Agency did in the aborted timeline of the War, becoming the Celestis. (PROSE: Alien Bodies)
 * In The End of Time, it is implied that the Doctor used the Moment when he became aware of the Ultimate Sanction and that most of the Time Lords had agreed to it, suggesting that the Time Lords' moral corruption was one reason the Doctor resorted to such drastic measures. In The Day of the Doctor, the Ultimate Sanction is only given a passing reference. Both episodes, however, show that the Doctor acquired the Moment prior to Rassilon gaining the approval of the other Time Lords. Hell Bent also indicates that not all Time Lords agreed with Rassilon's plans as the Doctor was hailed as a war hero and the entire Gallifreyan military turned on Rassilon given the chance.