Good Thinking was the name of a programme and a virus which had two strains; Invictus and Provictus. The first was engineered in 1955 by the United States as a weapon against communists (AUDIO: "Prodromal: Love" and the second by Heights Pharmaceuticals to infiltrate terrorist cells. However, a minister used Dr Frances Godalming in an attempt to infect the British public with Provictus for surveillance and mind-control. The plan was thwarted by Norton Folgate and Jack Harkness. (AUDIO: "Invasion: Kill")

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