Acting President of the High Council

The title of Acting Lord President, or Deputy President, (PROSE: The Five Doctors) could be bestowed upon an individual if the incumbent Lord President was not fit to lead (AUDIO: Appropriation) or by the President themselves in the event of their departure from Gallifrey for a prolonged period of time. (TV: The Five Doctors) The title was legally distinct from Lord President-elect.

The status of an Acting President necessitated an election in any case, (AUDIO: Appropriation) although in Valyes' case, the aftermath of the Gallifreyan Civil War and apparent destruction of the Matrix had put this on hold. (AUDIO: Warfare)

Powers
K9 Mark II corrected Acting President Valyes when he called Romana II the ex-President, stating that "the preposition quantifier 'acting' in your title indicates you hold the presidency for a finite amount of time only". In her tribunal, Romana stated that the appointment of Valyes as Acting President was a "temporary" measure. Despite this, in a later conversation Valyes, Commander Janartis and Coordinator Narvin all agreed that "technically" the statement that Romana was no longer President was correct, as did Inquisitor Prime Darkel separately. Romana herself expressed doubt as to whether she still held the position stating that it was a "moot point" whether she had any power at all.

Valyes suggested to Matthias that he could appoint him High Chancellor. He did appoint him as a Cardinal with some of the powers of Vice President which he immediately ratified with a vote of the High Council. Valyes also cleared Darkel of all criminal charges, in his dual positions as Chancellor and President.

The Acting President had a constitutional right to resign from the post. (AUDIO: Appropriation) Former Acting Presidents had the right to remain on the High Council, just as any ex-President had. (PROSE: The Eight Doctors) The incumbent of the role of Acting President could still name their successor, as Valyes did with Darkel. Acting President Darkel also had the power to call an election although it did not come to pass as Romana named herself as President, which would have required her to undergo a forced regeneration.

The Constitution stated that if a President was unable to carry out their duties and there was no Vice President then it was the right of the High Council to appoint an Acting President. However, at the time Romana was deemed unfit for office there was no High Council as she had declared herself Imperiatrix. In this case, as Councillor Delox stated, Chancellor Valyes was not appointed Acting President but rather power fell to him in the traditional manner. Romana stated that the lack of both a High Council and Vice President made this act unconstitional. (AUDIO: Appropriation) During the Borusa Interregnum, the High Council appointed Borusa as acting President for a short period after Niroc's corruption was revealed. (PROSE: The Eight Doctors)

When the High Council used its emergency powers to elect the Fifth Doctor President, he instead granted Flavia "full deputy powers" until his return (TV: The Five Doctors) and was under the impression as he told Tegan Jovanka that as long as he was still missing Flavia would remain in the post as Acting-President. In fact, she remained in the post for some time and achieved much. Flavia told the Sixth and Eighth Doctors that she had assumed the presidency "in irregular circumstances on a temporary basis" and admitted to them that through long use she had come to think of the presidency as hers. (PROSE: The Eight Doctors)

The High Council was unable to appoint a President if there was a legible Lord President-elect, (AUDIO: Mindbomb) even if they were offworld. (TV: The Invasion of Time) After the death of Chancellor Goth and the departure of the Fourth Doctor, the President-elect, (TV: The Deadly Assassin) the High Council ratified Borusa as Chancellor although the Fourth Doctor claimed this was illegal as his approval was strictly needed. (TV: The Invasion of Time)

Holders of the office
Flavia was made Acting President by the Fifth Doctor but resigned the post after hearing murmurings that she was elected undemocratically. She stood for re-election but was defeated by Niroc. After he was deposed and the Borusa Interregnum was over, she served as President proper for a time. (PROSE: The Eight Doctors)

Both Valyes and Darkel were named Acting President after Romana II was declared unfit for office however the issue of a vote of no confidence by the High Council to move Romana's tribunal forward logically recognised her presidency up to that point, negating the validity of their positions. (AUDIO: Appropriation)