Walter Jeremiah Matheson III was the most powerful businessman in the New Earth Republic.
He was so in love with the actress Dominique Delacroix that he helped the Autons make a perfect replica of her, a replica who was in love with him. He planned to aid the Nestene Consciousness escape from Polymos, which was being attacked by the Time Lords, and house itself in the Delacroix duplicate. He would then rule the galaxy with his ideal queen by his side.
However, the Sixth Doctor and the Auton replica of Marcus Brooks stopped Matheson's plan by trapping the Consciousness in the Delacroix copy. When the real Delacroix confronted him and made him face his own pettiness, he shot himself in shame. (PROSE: Synthespians™)