Poulenc’s opera about religious persecution in dark times has rarely been more devastating than in Olivier Py’s production for Paris’s Théâtre des Champs-Elysées last December. Breathtakingly conducted by Jérémie Rohrer, it boasts one of the finest casts ever assembled for the piece. Patricia Petibon gives the performance of a lifetime as Blanche, fleeing from the world into a convent, only to be faced with spiritual and political realities she can no longer avoid. Sandrine Piau’s Constance, Sophie Koch’s Mother Marie and Véronique Gens’s Madame Lidoine are equally outstanding, and even though Rosalind Plowright, as terminally ill Madame de Croissy, can be shrill, her performance has a dramatic veracity that is disturbing in the extreme. Py’s interpretation – updated to the mid-20th century yet never identifying which political system lurks beyond the convent doors – is deeply humane, but also teases out the complex theological issues that lurk behind the work. Long sceptical about the piece, I was completely won over – the highest complement I can pay it.