Trial

A trial was a formal examination of the actions of an individual, seeking to determine whether the individual had infringed some form of law. It could be held in a court, with the term of court applying both to the physical location of the trial, to the trial itself, and to the judging panel.

Officials
On Earth, trials were typically presided over by a judge. (AUDIO: Judoon in Chains) However, Gallifreyan trials could also be headed by a small group of representatives of the High Council, (TV: The War Games) by the Lord President (PROSE: The Legacy of Gallifrey) or by an Inquisitor. (TV: The Mysterious Planet)

Lawyers, or attorneys, would represent the accused, seeking to defend them via rhetorical argument directed to the judging court. (COMIC: The Court of Birds) In turn, a prosecutor would present an argument for the accused's guilt. On Gallifrey, "valeyard", a name adopted by a maleficent emanation of the Doctor, was an obscure term for a particularly learned prosecutor. (TV: The Mysterious Planet)

In 20th century Britain, the jury's role was the decide whether the evidence present was sufficient to condemn the accused as "guilty" or "not guilty", requiring unanimous agreement before the trial can be concluded (PROSE: The Juror's Story)

The Doctor's trials
Over the course of his long life, the Doctor was involved in many trials across his different incarnations.

For the murder of Roberta Sampson
The First Doctor was put on trial on Earth in 1963 for the murder of werewolf Roberta Sampson. He was acquitted of all charges. (PROSE: The Juror's Story)

For the breach of non-interference
The Second Doctor was put on trial on Gallifrey for the breach of their Non-interference policy. He was exiled to 20th century Earth and regenerated into his Third incarnation as part of his sentence. (TV: The War Games, Spearhead from Space)

For the murder of the Lord President
The Fourth Doctor was put on trial on Gallifrey for the murder of Lord President (TV: The Deadly Assassin) Pandad IV. (PROSE: The Legacy of Gallifrey) All charges were eventually dropped, after it transpired that Goth had been the murderer, under the influence of the Master. (TV: The Deadly Assassin)

For his general behaviour
The Sixth Doctor was put on trial in Space Station Zenobia for for his general behaviour, with Darkel serving as inquisitor and the Valeyard as prosecutor.

Notable trials
Vislor Turlough's inquisition was held at Government House in the 1970s following the Trion Civil War. He was exiled to Earth for his continued support of the Imperial Clans and loyalty to the Old Regime. (PROSE: Turlough and the Earthlink Dilemma)