A Time Lord was a member of the tribunal that sentenced the War Lord and the Second Doctor during their own separate trials.
This Time Lord, with two other Time Lords, on Gallifrey, had captured the War Lord. The second Time Lord explained what the War Lord and his people had done. He said that the War Lord's plans were "an utterly callous disregard for the lives of the humans involved, and for the liberties of all the other species in the galaxy."
When he asked the War Lord if he had anything to say in his defense, the War Lord refused to say anything. The second Time Lord used power to cause intense pain for the War Lord, thus he spoke, saying that the Doctor collaborated with the War Chief, and that if he was guilty then the Doctor was guilty too.
The second Time Lord sentenced the War Lord to dematerialisation, wiping him out of existence, after his verdict of guilty was reached. (TV: The War Games)