IT ISN'T every day that a new film features a former Church Times columnist; but The Invisible Woman (Cert. 12A) does just that: not Charles Dickens, an aspect of whose life is the film's chief concern, but the Revd William Benham.

Besides writing for the CT under the pseudonym "Peter Lombard", he edited William Cowper's poetry, and taught modern history at F. D. Maurice's foundation for girls and women, Queen's College, London. Benham was a great enthusiast for Dickens, and also pioneered links between the Church and the theatre.

We first see the eponymous woman, Nelly Robinson, née Ternan (Felicity Jones), walking disconsolately along a beach. It is 1883. At the school founded by Nelly and her husband, whom she has recently married, she has been rehearsing a play by Wilkie Collins and, more to the point, Dickens. This unleashes sad memories of her clandestine relationship with Dickens. She tells Benham, Vicar of St John's, Margate, that she now "loathed the very thought of this intimacy".

Thirteen years have elapsed since Dickens's death. In accordance with Claire Tomalin's book, on which the film is based, John Kavanagh plays Benham as a sympathetic listener. He is kindly, and in effect ends the film with absolution. In real life, it seems that Benham failed to honour Nelly's confidences - if not the seal of the confessional - passing them on within her lifetime to Dickens's biographer, Thomas Wright. The author seems to have been more discreet than the priest: he published Benham's revelations well after Nelly's death.

It is doubtful whether we would ever have known about her, or had this film, if it were not for this apparent clerical lapse. And that would be a loss; for it finely portrays the dilemmas proceeding out of human frailty, passion, duty, and love. Tomalin - naïvely, in my experience - suggests that the relationship between Dickens and Nelly would no longer be generally regarded as sinful. More realistically, the film does recognise their situation as a contemporary moral conflict.

Ralph Fiennes, both as director and protagonist, shows us how Dickens, whose advocacy of the poor had rendered him well-nigh a saint in the public eye, fears being compromised. Fiennes plays the part as a personality driven by the need for public adulation and unhappy with home life. Nelly's mother (Kristin Scott Thomas) aptly describes the Dickenses' matrimonial situation when telling her daughter: "Being married is at times the loneliest place."

This is true for Joanna Scanlan's sensitively portrayed Catherine as it is for Dickens. One could weep for the way in which she is marginalised by her husband. When he eventually departs their bleak house to be (secretly) with Nelly, literal shadows linger about them.

Unlike Collins (Tom Hollander), who openly despises marriage as a bourgeois convention, Dickens the Unitarian who has turned Broad Anglican craves respectability. It is too limiting to say that self-protective hypocrisy is the tribute that he pays to uphold an appearance of virtuous public standards. Rather, the film works best when revealing his shadow-side (and, by extension, ours), something that, left unacknowledged, becomes a burden not only to us, but to others, too.

Dickens, that great observer of the human condition, is unable to bring his own complexities into the light, and he leaves poor Nelly to shoulder the burden till Benham relieves her of it. At least the parson got that bit right in a film that is full of pity rather than blame.

On release from today.