Anthony Frieze
From Tardis Wiki, the free Doctor Who reference
Anthony Frieze (born 19 November 1965[1]) provided one of the voices of Xoanon in the Doctor Who television story The Face of Evil.
He was a student at the school where Pennant Roberts' wife taught at the time. Philip Hinchcliffe arranged for a recording of his voice to be made shouting, "Who am I?", for the climax to part three. After the initial recording (in a sound studio), Frieze made a second visit to the set and re-recorded the line.