The Birth of Hammer Horror (1955 to 1959)

Hammer's first significant experiment with horror came in the form of a 1955 adaptation of Nigel Kneale's BBC Television science fiction serial The Quatermass Experiment, which was directed by Val Guest. As a consequence of the contract with Robert Lippert, American actor Brian Donlevy was imported for the lead role, and the title was changed to The Quatermass Xperiment to cash in on the new X certificate for horror films.

The film was an unexpectedly big hit, and led to an almost equally popular 1957 sequel Quatermass 2 – again adapted from one of Kneale's television scripts, this time by Kneale himself and with a budget double that of the original: £92,000. In the meantime, Hammer had produced another Quatermass-style horror film, X the Unknown, originally intended as a full part of the series until Kneale denied them the rights.

At the time, Hammer voluntarily submitted its scripts to the British Board of Film Censors (BBFC) for comments before beginning production. Regarding the script of X the Unknown, one reader/examiner (Audrey Field) commented on 24 November:

"Well, no one can say the customers won't have had their money's worth by now. In fact, someone will almost certainly have been sick. We must have a great deal more restraint, and much more done by onlookers' reactions instead of by shots of 'pulsating obscenity', hideous scars, hideous sightless faces, etc, etc. It is keeping on and on in the same vein that makes this script so outrageous. They must take it away and prune. Before they take it away, however, I think the President [of the BBFC] should read it. I have a stronger stomach than the average (for viewing purposes) and perhaps I ought to be reacting more strongly."