X: The Unknown

X the Unknown is a 1956 British science-fiction horror film from Hammer Film Productions, directed by Leslie Norman and starring Dean Jagger, Leo McKern and Edward Chapman. The screenplay was written by Jimmy Sangster, his first for a feature film. In the film, a group of scientists and military personnel investigate a mysterious series of deaths by radiation exposure in rural Scotland. The film was originally conceived as a sequel to The Quatermass Xperiment (1955), but writer Nigel Kneale refused to let the character Bernard Quatermass be used, so the film was retooled into a standalone project. Original director Joseph Losey was replaced before filming began, purportedly due to disagreements with lead actor Jagger. X the Unknown was significant in that "it firmly established Hammer's transition from B-movie thrillers to out-and-out horror/science fiction" and, with The Quatermass Xperiment (1955) and Quatermass 2 (1957), completes "an important trilogy containing relevant allegorical threads revealing Cold War anxieties and a diminishing national identity resulting from Britain's decrease in status as a world power". As with Quatermass, Hammer played up the film's X Certificate in their advertising. The film premiered at the London Pavilion on 21 September, 1956. In the UK, the film was released on a double bill with Les Diaboliques. It was released in the United States on 2 May, 1957, on a double feature with The Curse of Frankenstein.