Jonathan Newth  Jonathan Newth (born 6 March 1939) is a British actor, best known for his performances in television. Credits include: "Emergency Ward 10", "The Six Wives of Henry VIII", "Ace of Wands", "The Troubleshooters", "Z-Cars", "Callan", "Van der Valk", "The Brothers", "Softly, Softly", "Poldark", "Doctor Who" ("Underworld"), "Notorious Woman", "Secret Army" (Barsacq), "The Professionals", "The Nightmare Man", "The Day of the Triffids", "Tenko" (Colonel Clifford Jefferson), "Triangle", "Angels", "Juliet Bravo", "After Henry", "The Adventures of Sherlock Holmes (The Bruce-Partington Plans), "Boon", "Bugs", "The Bill", "Agatha Christie's Poirot (Dumb Witness)", "Peak Practice", "Heartbeat" and "The Spire (Play at Sailsbury Cathedral)".