Prison governor (Frontier in Space)

A Prison Governor of Earth's Lunar Penal Colony once interacted with both the Third Doctor and the Master. He principally investigated the claims the the Doctor and Professor Dale had attempted to escape the prison on their own. He did not believe that they had in fact been set up by Cross, a prisoner who enjoyed the Governor's favour. When the Master, posing as an extradition agent from Sirius IV, requested that the Doctor be turned over to him, the Governor at first claimed greater right to the prisoner, and refused. However, when the Master threatened to reveal the whole trial as a farce, the Governor relented and surrendered the Doctor. (DW: Frontier in Space)
 * The novelisation greatly reduces the Governor's role in events. There is no trial at the Lunar Penal Colony; instead the Governor meekly recognises the president's authority and releases the Doctor to the Master.