Flavia

Flavia was both the High Chancellor and, following the Fifth Doctor's deputisation, at least the acting President of the High Council of Time Lords. According to Lady President Romana speaking at around the time of the Pandora incident, one of Flavia's legacies was this combination of the two highest offices. Speaking at the time of the Pandora incident, Romana claimed that no one had independently held the office of the High (or Lord) Chancellor since Flavia. (BFG: Pandora)

Ascension to the presidency
Flavia met with the fifth incarnation of the Doctor when Borusa summoned the Doctor's other selves to the Death Zone. She was sympathetic towards him. Following Borusa's defeat and entombment in the Dark Tower, the High Council granted Flavia the authority to make the Doctor President of the High Council. The Doctor used his emergency powers to put Flavia in charge, appointing her Acting President until he returned. He then escaped from his homeworld of Gallifrey, evading the responsibility the office of Lord President. (DW: The Five Doctors)

It was unclear whether Flavia ever won election or appointment to the office in her own right, or if she was always simply deputising for the Doctor. Whatever the case, Flavia later was deposed, according to one view of events, in favour of the political non-entity Niroc. The Celestial Intervention Agency wanted a President they could control more easily, to conceal the recent theft of important data from the Matrix. The Doctor was put on trial during this period. A Committee of Inquiry was opened into the trial. This was due to the actions of the Eighth Doctor and a temporal duplicate of the Sixth Doctor. The latter was created when the Valeyard tried to 'force' an alternate timeline where the Sixth Doctor was found guilty and executed. The Eighth Doctor awakened Borusa to quell the riots while the Sixth Doctor fought the Valeyard and the Master in the Matrix. (EDA: The Eight Doctors; DW: The Trial of a Time Lord: The Ultimate Foe)

When the Seventh Doctor was captured by the Committee of Three, his companions escaped and warned President Flavia of the danger. (NA: Blood Harvest)

Shortly afterwards, Ruath shot Flavia with a stunner to gain access to the Time Scoop. (MA: Goth Opera)

She learnt the Eighth Doctor was visiting his past seven selves for unknown reasons, bypassing all usual security protocols preventing such interaction. Flavia, despite the protests of the unscrupulous Time Lord Ryoth, decided to allow these visits to continue until they were proven to be a danger to Gallifrey. Once the visits were concluded, Flavia reflected that she wished the Doctor well in his future adventures. (EDA: The Eight Doctors)

End of political career
Conflicting accounts existed as to the manner in which Flavia's political career ended. At issue was whether Romana II had directly succeeded Flavia, or if there had been an intervening president.

One view held that Romana II simply contested Flavia for the presidency and won. (NA: Happy Endings) This  was later confirmed by Romana's direct recollection that the had invoked a so-called "right of challenge" against her predecessor, just as Darkel later challenged her. (BFG: Insurgency)

However, there was evidence of an intervening president. On another occasion, Romana said she had been "asked to become President after the coup that overthrew Flavia's inauspicious reign", in spite of her lack of political experience – suggesting another President, Niroc, ruled in an interim term. (BFG: Lies)''

Behind the scenes

 * The character of Flavia filled in for that of Thalia, who had appeared in the earlier story, Arc of Infinity. The production team decided not to simply recast the role using the excuse of regeneration and made up a new character.
 * According to various commentaries on the Series 1 and 2 DVDs, Russell T Davies refers to the lilting female vocal in the musical score as 'Flavia's Theme'.
 * The character of the Inquisitor is never referred to by name during her appearances in the fourteen-episode The Trial of a Time Lord arc. Although the name Darkel has been assigned to her by spinoff media, it is also speculated that the Inquistor might have been a regenerated Flavia. However, this is highly unlikely as Time Lords tend to recognise each other after regenerations. (DW: The Twin Dilemma, The Armageddon Factor, The Five Doctors)
 * According to The Brilliant Book 2012, a book that contains non-narrative-based information, after she became President, the Corsair tricked Flavia into revoking the censure put on him/her for the theft of the Portrait of Rassilon. She gave in to his smile and revoked the censure.