The conventional cinematic portrayal of unconventional parents, particularly those of a left-wing bent, is as wacky, irresponsible people who place bizarre ideals above their progeny's need for a nutritious supper and regular music practice. From Mrs Banks, the mother in Mary Poppins who would rather campaign for "Votes for Women" than stay at home and tidy the nursery, to Hideous Kinky, the tale of a hippie chick (played by Kate Winslet) who hauls her two young daughters through a series of exotic adventures in North Africa, film has captured the clash between adult self-absorption and the childish need for security and attention.
Blame It On Fidel, a low-key masterpiece out now on selected release, is the latest addition to the genre. Directed by Julie Gavras, daughter of Costa-Gavras, one of the most successful political directors of the 1960s and 1970s, and starring Julie Depardieu (daughter of the actor Gérard), it delicately explores the effect of the sudden politicisation of a lawyer and a journalist on their young daughter. The film opens in 1970 and is set in the world of haute bourgeoise France, with its stiff white tablecloths, its vast gardens and its impeccable manners. Nine-year-old Anna de la Mesa, played with astonishing range and acuity by Nina Kervel-Bey, observes as her parents plunge into radical campaigning and the family moves from its spacious house on the outskirts of Paris to a cramped flat in the city, filled with a succession of strange nannies, exotic food, hirsute revolutionaries and heated argument.
Anna fiercely and comically resists the re sultant change in her lifestyle. Repelled by easy political slogans about "group solidarity", she is forever switching off lights in an attempt to save the family finances and propel the de la Mesas back to their comfortable old life. She is allowed to stay on at her strict Catholic school, but only on condition that she be taken out of divinity classes, her favourite lessons.
As someone who lived through a radical childhood, albeit of a rather more mainstream kind, I recognised both superficial details and a deeper truth at work in this film. From the mid-1960s onwards, left-wing politics shaped the lives of both my parents, Tony and Caroline Benn. It was not uncommon to come home from school to find a roomful of bearded academics or a bevy of trade unionists insistently debating the future of socialism, or a circle of earnest teachers and parents sitting cross-legged on the floor, surrounded by leaflets, plotting the end of grammar schools. I loved the hum of all this collective activity, the coming and going, the ringing phones and doorbell, as well as the sense of being connected to outside events, however troubling or traumatic.
Like Anna and her brother, François, my siblings and I were moved in the mid-1960s from the ordered environment of private to local state schools. Such is the English obsession with class, that this change was seen in some circles as akin to child slaughter. Overnight, long-standing relationships were ruptured. We became curiosities, a living social experiment. Although we remained in the middle class, we were not quite of it - at least not in the old, unthinking ways.
Blame It On Fidel beautifully captures the emotional undertow of such situations, especially for a child. Like in The Lives of Others, this year's Oscar-winning study of East German artistic dissidents and miserable spies, the clash of values is conveyed much as it is experienced - through colours and textures. The interiors of Anna's rather brutal anti-communist maternal grandparents' house and her school appear increasingly sterile and chilly, while her chaotic parents, their political friends, and the Paris flat itself are richly lit, brimful with warm colours.
There are, without doubt, many important gains of a political upbringing. With an admirably light touch, Gavras shows us how Anna slowly opens up to the world. In one scene, she pores over a map of Chile at the local library, curious about the details of this country that so engages her parents' sympathies. On a trip back to her father's childhood home in Franco's Spain, from which her activist aunt and her cousin have fled when her uncle is killed, she begins to fathom the complex wellsprings of his powerful but tormented motivation.
Some might interpret Blame It On Fidel as a communist version of Hideous Kinky: as the story of a neglected - or even indoctrinated - child. In fact, it is far better understood as a subtle tale about a profound shift of sensibility, one human being coming to understand the true meaning of solidarity. When her father stands, dumbstruck with despair at the 1973 coup in Chile, Anna slips her hand into his, offering support. In a final, moving aerial shot, we see her standing alone among the swirling crowd in the playground of her new neighbourhood school. Slowly, a circle of girls breaks rank, and a hand stretches out to draw her in. Anna's journey from prissy convent girl to sympathetic and in tegrated human being is complete.
Melissa Benn's new novel, "One of Us", will be published next spring by Chatto & Windus