High Council

The High Council, sometimes called the Supreme Council or High Council of Time Lords, was the governing body of the Time Lords on Gallifrey, composed of the Lord President (TV: The Invasion of Time) and Cardinals elected from the ruling Houses. (TV: The Ultimate Foe)

Officially, without a President, the Council could ratify nothing, even if this occurred in exceptional cases such as the absence of the President-elect. (TV: The Invasion of Time)

Membership
The Inner Council consisted of the President, the Chancellor, (TV: The Deadly Assassin) and the Castellan. (TV: The Five Doctors)

Other offices associated with the Council included the Gold Usher (TV: The Deadly Assassin), the Surgeon General (TV: The Invasion of Time) and the Inquisitor. (TV: The Trial of a Time Lord)

History
At the end of the trial against the Sixth Doctor and the revelation of the Time Lord's involvement in the Ravolox affair, insurrections burst on Gallifrey and the High Council was deposed; new elections were announced. (TV: The Ultimate Foe)

By time of the Last Great Time War, the Time Lords had resurrected Rassilon, who returned to lead the High Council against the Daleks. At least an emergency session of the council was arranged, when the War Doctor and his companion Cinder landed on Gallifrey, bringing news about the Temporal Cannon of the Daleks. It was the first time a human had been allowed to attend such a meeting. (PROSE: Engines of War)

By the last day of the war, the High Council met in a darkened chamber in the ruined Citadel. They met there on the last day of the war to discuss Rassilon's Final Sanction. (TV: The End of Time)

While this was happening, the War Council threw away the High Council's plans and made some of their own. (TV: The Day of the Doctor)

When Clara Oswald pleaded with the Time Lords to save the Doctor, the High Council decided to grant him a new regeneration cycle. (TV: The Time of the Doctor)

After the Twelfth Doctor returned to Gallifrey, by this point hidden at the end of the universe, Rassilon sent them out to meet the Doctor who merely walked back inside the barn he had slept in as a child. Rassilon was ultimately forced to come greet the Doctor himself. After overthrowing Rassilon, the Doctor banished him and the High Council from Gallifrey for their roles in both his imprisonment and their crimes in the Time War. (TV: Hell Bent)

Known members of the High Council
Members of the High Council included Councillor Hedin; (TV: Arc of Infinity) Councillors Rath, Elar and Morin; (PROSE: Blood Harvest) Councillor Delox; (AUDIO: Appropriation) Councillor Ryoth, a member of the Arcalian Chapter and a member of the Celestial Intervention Agency; (PROSE: The Eight Doctors) Surgeon General Lord Gomer; (TV: The Invasion of Time) the Gold Usher; (TV: The Invasion of Time) Inquisitor Prime Darkel; (AUDIO: Weapon of Choice, Mindbomb) Councillors Flavia, Engin and Ortan; (PROSE: The Eight Doctors) Councillor Ragnar, a member of the Prydonian Chapter; Councillor Milvo, a member of the Arcalian Chapter; Councillor Sardon, a member of the CIA; (PROSE: World Game) Councillor Ratisbon a member of the CIA; (PROSE: Warmonger) Coordinator Narvin, head of the CIA; (AUDIO: Gallifrey (audio series)) Councillor Romana II; (PROSE: Blood Harvest, Human Nature) Councillor Wblk; (PROSE: Heart of TARDIS) Councillor Verne; (PROSE: The Twin Dilemma) Cardinal Matthias; (AUDIO: Mindbomb)

During the Last Great Time War, Grayvas (PROSE: Engines of War) and Ollistra were Cardinals. (AUDIO: The Innocent) Lord President Rassilon headed the High Council, with the Chancellor; the Visionary and the Partisan also on the Council. (TV: The End of Time)

Following the end of the Time War, there were shown to be only a few councillors, meeting with Rassilon about the Doctor's return and attempting, unsuccessfully, to speak to the Doctor himself. After the Doctor overthrew Rassilon, he banished him and the High Council from Gallifrey. (TV: Hell Bent)

Behind the scenes
According to DWM 100, the full High Council was a large body, similar to a Parliament.

Alto Conselho