Having found a cure to the illness, the Doctor discovers that it is in fact deadly nightshade poisoning which has been introduced into the city water supply.

Ian Hogg (born in Newcastle upon Tyne) is a British actor.

He is the son of a doctor and was educated at Durham School, Durham University and the Central School of Speech and Drama. He then joined the Royal Shakespeare Company.

He has appeared in many television and film roles including the 1996 program Rasputin, Mike Cherry in EastEnders (1999) and Alois Hitler in Hitler: The Rise of Evil (2003). Hogg played the role of Edmund in Peter Brook's 1971 film version ofShakespeare's King Lear. He is best known for his lead role in the BBC1 television series Rockliffe's Babies and its follow-up Rockliffe's Folly, playing Detective Sergeant Alan Rockliffe. He also appeared in Doctor Who as the villain Josiah Samuel Smith in the serial Ghost Light (1989) and he has also more recently been associated with the show by appearing in The Sandman—a spin-off audio drama produced by Big Finish Productions. In the summer of 2008, he played in repertory in Scarborough, North Yorkshire at the Stephen Joseph Theatre under the artistic direction of Alan Ayckbourn.

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Jolyon Booth played Prapillus in the 1965 Doctor Who television story The Web Planet.

She gave up acting to become a school teacher.

Appeared in Georgy Girl, Gideon's Way, The Baron, The Plague of the Zombies, ITV Play of the Week, The Man in Room 17, Armchair Theatre, Crane, Z Cars, Victoria Regina, No Hiding Place

Born in Plymouth in 1904, the actress had a lengthy stage career before taking on a number of roles on television in the 1960s, including adaptations of Lorna Doone, Nicholas Nickleby and The Woman in White, and guest starring in longer running series like Dr Findlay's Casebook and Z-Cars. Other roles followed in the 1970s, but the role for which she'll be remembered most fondly is as Mrs. Polouvicka in the series To The Manor Born.

She played Martha Tyler in the 1977 Doctor Who serial Image of the Fendahl.

George Gertan Klauber was a British character actor.

He played small roles in many of the Carry On films and appeared in numerous television productions, often playing minor villains, including episodes of The Saint, The Professionals, Danger Man, The Avengers twice in Doctor Who as The Galley Master in The Romans and as Ola in The Macra Terror and as mad king George III in Blackadder the Third..

He was married to the British actress Gwendolyn Watts.

_{Biography from the Wikipedia article, licensed under CC-BY-SA}

Actor who had two roles in Doctor Who, playing William des Preaux in the 1965 story The Crusade and returning in 1982 to play  Captain Urquhart in Time Flight