Dusting off the ancient archive files for the 1959 Hammer production of The Mummy, starring Peter Cushing and Christopher Lee, we find documents which detail script advice given to Hammer by the BBFC.
A script written by Jimmy Sangster was sent to the BBFC in February 1959 prior to shooting. The BBFC were familiar with Hammer horror films by this time, having previously classified films such as The Curse of Frankenstein (1957) and Dracula (1958). Recurring elements of the script to be noted as potential classification issues include the various instances of 'throttling' and the sounds of bones crunching.
Following the initial response to their script Hammer sent an amended version to the BBFC for further advice. The second script featured a new sequence set in 2000 B.C. and a revised ending. These major changes did not particularly trouble the BBFC, but there is some comment on the idea of "transparent or non-existent" nightwear. Concern also remained about the sounds of "bones snapping" in the film.
The finished film was submitted for classification in May 1959, and was seen in black and white. The BBFC considered an A certificate at this point - that would indicate the film was more suitable for adults, but with no age restrictions - but delayed the decision until the colour version was available. The impact of the colour presentation was such that it pushed the film into the X category (over 16s only).