Read more about The Valeyard at: Wikipedia

Official Site: BBC

The Valeyard is a fictional character from the long-running British science fiction television series, Doctor Who. He is described as an amalgamation of the Doctor from between his twelfth and final incarnations as depicted in the TV show or regenerations in the novelization of the story. In the serial The Trial of a Time Lord, comprising the whole of Season 23 of the series, the High Council of the Time Lord appoint the Valeyard as prosecutor at the Sixth Doctor's trial, hoping to have him executed and thereby removing the sole witness to their near-destruction of life on Earth.

The Valeyard appears in all four segments of the 1986 serial The Trial of a Time Lord — The Mysterious Planet, Mindwarp, Terror of the Vervoids and The Ultimate Foe. In episode 4 of The Mysterious Planet it is stated that "valeyard" means "learned court prosecutor" in their language, although the term is obsolete and highly obscure.

During the course of the trial, the Doctor was accused of "conduct unbecoming a Time Lord" and transgressing the First Law of Time. As prosecutor, the Valeyard presented the events of The Mysterious Planet and Mindwarp as extracts from the Matrix, the computer network that serves as the repository of all Time Lord knowledge. The Valeyard used these extracts as evidence of the Doctor's meddling in time and space. Throughout the presentation of the evidence the Doctor barked at the Valeyard, calling him names such as "the Boneyard," "the Scrapyard," and "the Knacker's Yard," and only the interventions of the Inquisitor, another Time Lord, kept the trial going.

What was not discovered until later was that the Matrix extracts had been tampered with to show the Doctor in the worst possible light, the Doctor unable to directly contradict some of the actions shown as his own memory of the events depicted was hazy due to his extraction from time having disoriented his memory. In The Mysterious Planet this involved the editing of particular scenes. Scenes of the mercenary Sabalom Glitz attempting to buy "secrets" from the robot Drathro were censored completely. In Mindwarp substantial portions of the extract were falsified entirely by the Valeyard. The most significant alteration was when the Time Lords intervened in the brain transplant experiments of Lord Kiv and his scientist Crozier. In the Matrix extract, it appeared that Yrcanos was manoeuvred into killing the Mentors after Kiv's mind had been transplanted into the body of the Doctor's companion Peri – the Doctor having apparently betrayed Peri to save himself after exposure to one of the machines in the lab temporarily altered his personality – effectively killing her.

The Valeyard has not been a contender in any CBUB matches.