This 35mm screening is part of the John Carpenter season at BFI Southbank and can also be seen on October 22nd. Full details here.
Chicago Reader review:
Genre specialist John Carpenter returns to the principle of confined space that he used as a disciplinary structure in Assault on Precinct 13 and The Thing in this 1987 horror thriller, set in an abandoned church. The main difference here is the heavy metaphysical baggage: a team of graduate science students and teachers is summoned by a Catholic priest (Donald Pleasence) to study an ancient religious manuscript that proves to contain differential equations (written long before such equations were developed), and a canister containing a green liquid that proves to be seven million years old. Mathematics combines with demonology to produce a variant on Night of the Living Dead, and while the church is playfully called Saint Godard's, the pivotal use and significance of mirrors spawned by the canister liquid might make Saint Cocteau's more appropriate. While the dense significations of the script may get a bit thick in spots, Carpenter's handsome 'Scope images generally make the most of them. Some haunting poetic notions —such as video images from the future that appear as recurring dreams to the church's inhabitants—also figure effectively in the plot.
Here (and above) is the trailer.