Having recently signed a two-year extension to his BBC staff writer's contract, Nigel Kneale was specifically commissioned to write a sequel to "The Quatermass Experiment" in early 1955 to challenge the new ITV network. Kneale was inspired by contemporary fears over secret UK Ministry of Defence research establishments such as Porton Down, and also by being required, as a BBC staff member, to sign the Official Secrets Act. As with "The Quatermass Experiment", "Quatermass II" was produced and directed by Rudolph Cartier; he and Kneale particularly enjoyed working together. Since the first "Quatermass" serial, the two men had collaborated on the literary adaptations "Wuthering Heights" (1953) and "Nineteen Eighty-Four" (1954), and on Kneale's abominable snowman play "The Creature" (1955).