Originally begun as an impartial inquiry into the behaviour of the Doctor, the Sixth Doctor’s trial was brought about due to the significant loss of human life in the prosecution’s first evidence. The prosecutor was the Valeyard and Darkel acted as inquisitor, presiding over the evidence. The Doctor refused the right of a court defender. The Valeyard’s award for winning was the Doctor’s remaining regenerations.
The Doctor was taken out of time at a critical moment by the Time Lords and placed in Space Station Zenobia when he arrived in court. The initial charge was that “he, on diverse occasions [had] been guilty of behaviour unbecoming of a Time Lord”. The Doctor denied the charges. Before the first evidence was presented, discussion of the Second Doctor’s trial took place where it was highlighted that the Valeyard deemed the punishment to be too lenient.
The Valeyard’s first evidence was the Doctor’s involvement in the affairs of Ravolox. At some points, the sequence had been censored by the High Council because the information contained within were deemed not suitable for the public. Although the Valeyard offered Darkel the opportunity of consuming it privately she denied as it was unfair to the defendant. After the sequence on Ravalox had finished the Valeyard escalated the inquiry to a trial punishable by death because the Doctor’s meddling had caused the loss of human life, or at least more than if he had not interfered. (The Mysterious Planet)
The Valeyard’s next evidence was the adventure the Doctor had been involved in concurrently to his removal from time on Thoros Beta. During its course, the Doctor accused the evidence from the Matrix to be slightly altered to portray him as harsher. Also notable was the death of the Doctor’s companion, Peri Brown arguably as a result of the Doctor’s actions as well as the use of Yrcanos as an assassin by locking him in a time bubble so he could completely destroy Crozier’s experiments. (Mindwarp)
The Doctor’s first evidence was taken from his future; his defence being the fact he would improve. Over the course of the sequence the Doctor again accused the Matrix of presenting false evidence namely a sabotage he supposedly committed and encouragement into danger directed at his companion, Mel. At the conclusion of the adventure, the Doctor completely destroyed the Vervoid race to prevent them wreaking more havoc and death if even a single leaf landed on fertile soil. Latching onto this, the Valeyard invoked article 7 which prohibited genocide, claiming it allowed no exceptions. (Terror Of The Vervoids)