"Fiend Without a Face" created a public uproar after its premiere at the Ritz Theater in Leicester Square. The British Board of Film Censors has already demanded a number of cuts before granting it the "X" certificate.
In the USA, MGM distributed this film second on a double-bill with Torpedo Run starring Glenn Ford and Ernest Borgnine.
The Criterion Collection DVD has a hidden gag on it added by the authors. If you check the disc name/ID on a PC through various means, the ID reads AFIENDINNEEDISAFIENDINDEED, i.e. "A fiend in need is a fiend, indeed".
This 1958 British production was based on "The Thought-Monster" by Amelia Reynolds Long, which was published in the classic American pulp magazine "Weird Tales" in 1930.