Time Out review:
Hammer's second attempt at a Dennis Wheatley black magic thriller bears little comparison with the earlier The Devil Rides Out. It is very much a contemporary post-Exorcist movie, full of rampaging foetuses, obscene pregnancy rituals, and stray sexual suggestions as Lee's excommunicated priest and his satanist followers hound young Nastassja Kinski with malevolent intent. The film's unlikely trump card is Richard Widmark as a credibly sceptical supernatural investigator, who romps through the proceedings with a disarming stoicism, but regrettably faces his devilish opponent Lee only in the closing sequence.
Here (and above) is the trailer.