A Quiet Passion, the biopic of Emily Dickenson by Terence Davies, reproduces the boredom, disappointments and suffering of its subject’s life in such remorseless detail that it inflicts those same ordeals on the audience. Her fatal illness having been revealed, I found myself willing the poor woman to die so that I, too, might be spared further torment. Others did not wait so long and left before the end, the dull clatter of seats like sarcastic applause. Yet the house felt divided, it is fair to say. Dickenson inspires great reverence among fans, groups of whom took their places just before the film started, like militants packing a meeting. As with Sylvia Plath, it is less the poetry that excites their devotion than her treatment by men, the result being a shrill traumatology, a cult of the martyr’s wounds. With that in mind, the passion of the film’s title, which could refer to the poet’s thwarted love or immersion in her work, more closely resembles the Christian meaning of the word, a mixture of sacrifice and mortification. Her pious kinfolk would be dismayed.

But it is not just the length of the film that palls – a little editing would have sorted that out. In places the dialogue consists almost entirely of aphorisms, recalling Monty Python’s Oscar Wilde sketch. Were people really so persistently droll in the nineteenth century? The transition from younger to older versions of the characters is addressed by means of some clunky photoshopping, except in the case of Dickenson’s father, played throughout by Keith Carradine with the help of the make-up department and a bit of acting. We are treated to some of the most obvious hairpieces ever worn on screen, and the accents of the largely British cast make one curious about what lies beneath – like wigs, in fact. Finally, the images we are shown of battlefields with death tolls overlaid are stylistically at odds with the rest of the film. Nor is it clear what point they are trying to make. The Civil War must have impacted even on lives so cloistered and self-obsessed. But after Emily’s brother, Austin, is forbidden to enlist the subject very quickly drops out of sight. That said, the photographs of Gettysburg are transfixing, the images of Lincoln like seeing a mythological figure brought to life. But which side the Dickensons were on is never specified, apart from some waspish comments about slavery.

The film’s redeeming feature is a committed, immersive performance by Cynthia Nixon. She inhabits the part with an almost occult intensity, giving us an individual with all her contradictions laid bare: brilliant, loyal, cantankerous – and, it must be said, increasingly difficult to like. The climax is an extraordinary enactment of the poet’s agonies and death throes, so convincing they become almost unbearable to watch. Of course, the trouble with such magnetism is that it drains the life from other characters. Her sister Vinny, played by Jennifer Ehle, is too selfless to be credible, and their brother Austin (Scotland’s Duncan Duff) blurts out his lines as if the chance might not come again. Only in their mother does such effacement make sense, a woman’s place thought natural by that generation, her daughters’ independence of mind hard to explain.

But what about the poems? Nixon recites them as a running commentary which keeps our interest afloat even when the dourness and disappointments of Emily’s life threaten to overwhelm. I freely admit to being ignorant about the work, but what I hear sounds uneven in quality, some lines penetrating, even profound, others as trite as greeting cards. Every writer needs advice, the editorial function almost as vital as creativity itself. Sequestered among her family, it may be that Dickenson missed the blue pencil of someone appreciative but better qualified to judge. Or, as her advocates might insist, she transcends such concerns with originality and directness of expression, a female kind of genius too easily scoffed at by men. For all its faults, Terence Davies’ film sends the audience back to their bookshelves with an age-old question in mind: must literature stand or fall on its merits, or is knowing about the author essential to understanding their work?