This 35mm screening, introduced by Emily Wilson of Cambridge University, is part of the Big Screen Classics season at BFI Southbank. You can find the full details here.
Chicago Reader review:
This 1966 film is probably the most punishing and intense of Robert Bresson's studies of modern martyrdom, a story of a teenage peasant girl whose experiences of the world lead her, irresistibly, to suicide. If you don't know Bresson's work, this isn't the place to start (you may never go back), but it's a remarkable film: dark, compressed, shattering. Nadine Nortier heads a nonprofessional cast; adapted from a work by Georges Bernanos.
Here (and above) is the trailer.