Some stars are irresistibly watchable whatever they appear in. Hollywood used to be over-run with them. But even arthouse cinema has had its share of icons and few have been more consistently compelling than Gérard Depardieu. Always a courageous actor, he has invariably selected projects that interest him rather than those that will satisfy his fans and My Afternoons With Margueritte is certainly one of his more esoteric choices. Adapted from a novel by Marie-Sabine Roger, it doesn't quite have the intellectual or emotional depth to sustain either its weightier themes or Jean Becker's cluttersome use of flashbacks and reveries. But this darkly whimsical celebration of life and literature is nevertheless beautifully played by Depardieu and his veteran co-star, Gisèle Casadesus.

Depardieu essays a slow-witted handyman, who lives in a trailer in the garden of mother Claire Maurier's rural village home. Deeming him an accident and a nuisance, Maurier has always treated him abominably and every attempt at communication culminates in her shrieking abuse. Depardieu spends much of his spare time in the bar that 50 year-old Maurane runs with her Arab lover, Lyès Salem. Lacking in the most basic social skills, Depardieu teases Maurane about the age difference and also makes insensitive remarks about mechanic Patrick Bouchitey needing to get over the death of his wife, while clumsily attempting to matchmake buddy Matthieu Dahan with newly arrived nurse Mélanie Bernier. However, not even being periodically ejected by chef Jean-François Stévenin can knock any sense into Depardieu and his friends struggle to see what bus driver Sophie Guillemin sees in him.

But she's not alone in regarding Depardieu as a gentle giant who could benefit from a little love and attention. Octogenarian Gisèle Casadesus first encounters him while he's counting pigeons on a bench in the park and is quietly amused by his literal response to her polite conversational gambits. Yet she is soon reading Albert Camus's The Plague to him and the initially reticent Depardieu comes to enjoy picturing the action in his mind's eye. However, he refuses her offer to take the book home and returns the dictionary she gives him, as he has always had trouble with words.

Between chores and trips to the nearby farmers' market, Depardieu experiences flashbacks to his awful schooldays and the humiliations his mother heaped upon him in front of the neighbours and her live-in lover. But he never lets anything get him down for long, until Casadesus confides over tea in her room at the old people's home that she is losing her sight and will soon have to rely on him to read to her. Touched by her plight, Depardieu carves a cane to help her get around the streets and asks Guillemin to coach him so that he can tackle simple texts without making too many mistakes. But, just as Depardieu learns that Guillemin is pregnant, Maurier dies and Casadesus is forced to move back to Belgium, as her nephew can no longer afford her fees.

Few will be surprised to learn that all ends happily, as this is a remorselessly feel-good saga that is marbled with the cosy conviviality that Becker brought to Strange Gardens (2003) and Conversations With My Gardener (2007). With anyone but Depardieu in the lead, this would coalesce into sticky sentimentality. But he deftly underplays the doltish gaucheness and selfless generosity that make his character as ingratiating as he's infuriating. Casadesus and Guillemin provide affectionate support and if the script occasionally contrives too hard to allow Depardieu to apply his new-found wisdom to everyday situations, it also enables Becker to tell his story with considerable humour and charm.

The need to survive drives three Mexican siblings to extremes in Jorge Michel Grau's We Are What We Are, which bears a passing resemblance to both Tomas Alfredson's Let the Right One In (2008) and Giorgos Lanthimos's Dogtooth (2009). Essentially, this puts a fresh spin on the old maxim that the family that slays together stays together. But Grau is as much interested in the pressures facing juveniles to assume adult responsibility as in providing gory jolts.

No one seems unduly concerned when Humberto Yáñez collapses and dies in a Mexico City shopping mall. Even the discovery of a woman's fingernail in his stomach during the autopsy raises no eyebrows and he is deemed so insignificant that nobody bothers to delve into his past. However, Yáñez not only leaves widow Carmen Beato to rear their three kids, but he also forces Francisco Barreiro, Paulina Gaitan and Alan Chávez to decide which of them is going to ensnare the victim for their next ritualistic cannibal feast.

None of the trio has any experience of life outside the home where they repair watches to make ends meet. Moreover, Barreiro is having a sexual crisis to rival his hunger for fresh flesh. Eventually, the brothers go in search of prey and resort to a prostitute when street kids prove too elusive. Beato, who suspected Yáñez of cavorting with hookers, refuses to perform the customary candlelight rite and the chastened boys quickly develop an audacious hunting instinct that enables them to seize by-passers with impunity and even prompts Barreiro to take his chances in a gay disco. However, their spree doesn't go unnoticed and even dull-witted detective Jorge Zárate manages to pick up their trail.

By focusing on the domestic dynamic, Grau achieves a claustrophobic intensity that is superbly reinforced by cinematographer Santiago Sanchez's blend of long, static takes and gliding tracks, and Enrico Chapel's oppressive score. But the need to introduce some horror alleviates the tension and Zárate's dogged investigation and the more graphic scenes of feasting often feel like intrusive sideshows to Beato's ravings, Chávez's edgy outbursts and Gaitan's possibly incestuous relationship with Barreiro. However, the debuting Grau directs steadily and laces proceedings with small moments of jet-black wit.

By contrast, an air of earnestness informs A Day in the Life - Four Portraits of Post-War Britain, a BFI release that showcases a quartet of documentary shorts by John Krish, one of the unjustly forgotten film-makers who provided a crucial link between the pioneering work of the British Documentary Movement in the 1930s and the practitioners of the more iconoclastic Free Cinema of the late 1950s. Krish went on to direct the chic opening credits for The Avengers, as well as several features and numerous commercials and public information films. But his particular talent lay in blurring the line between fact and fiction to give educational films a stylistic ingenuity to enhance their social relevance and efficacy.

Capturing the wave of nostalgia that swept through London during Last Tram Week, The Elephant Will Never Forget (1953) is a shamelessly sentimental paean to a form of transport that had served the capital for 91 years. Much of the 10-minute running time is taken up by a Cockney couple riding along the Embankment and the streets of South London and reminiscing about a music-hall song from their youth. Yet this simple evocation and the footage of the 20,000 Londoners bidding farewell to the last trams on 5 July proves deeply stirring and leaves one questioning the decision of Edgar Anstey, the head of British Transport Films, to sack Krish from his post for disregarding the company's rule about looking to the future rather than dwelling fondly in the past.

The kids en route from Birmingham to Weston-Super-Mare live very much in the present in They Took Us to the Sea (1961), a vibrant film sponsored by the NSPCC that conveys the excitement of an excursion at a time when few urban youngsters got to leave their own neighbourhood, let alone the city itself. From the moment they gather at Snow Hill station, the children used to playing in bomb sites and slum streets can barely contain themselves and they are soon sitting three to a seat and gazing out of the window at the passing countryside, reading comics, scarfing snacks and joining in sing-songs. And they become even more animated after a slap-up fish`n'chip lunch on the pier, as they dash on to the beach to ride donkeys and horse-drawn buggies, build sandcastles and paddle in the sea.

Afternoon tea is then followed by a trip to the funfair, with rollercoasters, dodgems and candy floss machines rounding off the perfect day and exhausting the last ounces of energy before the party returns home. Everyone seems to have enormous fun and Krish catches the mood without intruding upon the enjoyment. In Our School (1962), however, he exercises a firmer hand in recording a day in the life of Francis Combe Secondary Modern in Hertfordshire Consequently, this is a rather stiff study of how students respond to new approaches to lessons that often betrays the fact that it was produced under the auspices of the National Union of Teachers.

Opening with the entire school praying in assembly, the action slips between classrooms like a visiting governor to watch maths, art, home economics, welding, technical drawing, history and English being taught more through a combination of discussion and practice than dry book learning. However, one is always aware that Krish's version of direct cinema owes more to construction than observation. Thus, while the debate about accents and eloquence, the session on expectations with the 15 year-old girls about to leave full-time education and the personal accounting class all have their lively moments, they also feel stage-managed, despite the evident efforts to mitigate against performance.

Even I Think They Call Him John (1964) feels rehearsed rather than recorded. Nevertheless, this is a deeply moving portrait of John Cartner Ronson, a widowed veteran of both the trenches and the Home Guard, who now lives alone with his budgerigar Peter in a soulless block of London flats. He rises without enthusiasm on this particular Sunday morning and breakfasts on a boiled egg and toast before settling down to write to his sister-in-law in the States. He then potters into the kitchen to cook two sausages and a potato for his lunch and dreams about his past as he dozes the afternoon away on a hard-backed chair.

Occasionally, John stares out of the window at an estate that could never be called a community. But his sole human contact comes courtesy of Bruce Forsyth, as he watches Sunday Night at the London Palladium while doing his ironing. It's a sorry way for a noble life to wind down. But Krish - working on behalf of the Craignish Trust - reminds us that old age will eventually catch up with most of us and urges his audience to spare some time for those who have done so much for the country and are now in danger of being forgotten.

If this engaging compilation provides an invaluable snapshot of our yesterdays, a decidedly more troubling view of the future is presented by Danish documentarist Michael Madsen in Into Eternity, as he examines the possible ramifications of burying thousands of tons of nuclear waste in a vast network of underground chambers at the remote Finnish facility of Onkalo. Translating as `hiding place', this ambitious enterprise is due to be completed and sealed some time in the next century. But Madsen wonders what is to stop anyone stumbling across the complex in any of the 100,000 years it will take for the radioactive material to lost its potency from opening it up and subjecting the planet to hideous dangers.

Ably assisted by editors Daniel Dencik and Stefan Sundlöf, Madsen adroitly juxtaposes Heikki Färm's futuristic images of a cool water storage plant with more primeval shots of the tunnels being excavated by anonymous labourers, whose drilling and blasting occasionally seems to disturb the caribou grazing in the winter wonderland above. Madsen himself appears periodically to strike a match in the cavernous darkness and pose another question about the site's safety and the strategies that are being implemented to prevent future catastrophe. But he wisely leaves the bulk of the reassuring and speculating to the Finnish and Swedish scientists, politicians and business executives who have devised and commissioned Onkalo, as their admissions of ignorance and occasional misgiving prove far more powerful than any editorial rhetoric.

Given that the half-life of the waste is roughly equivalent to the span of human history, it's clear that its safe storage is subject to many imponderables. There is no guarantee, for instance, that a system of graphic or pictographic warnings will be decipherable by generations to come. Moreover, even if such markers did stand the test of time, it cannot be presumed that they will dissuade future discoverers from defying them - after all, ancient admonitions and curses have done little to deter archaeologists and treasure seekers.

But, while the various men in suits (and their sole female colleague) concede that they are placing an inordinate amount of trust in acceptance winning out over curiosity, they are actually impressively confident about the project's engineering aspects. Indeed, the subterranean system does seem infinitely preferable to the pools and tanks currently being used to house a global stockpile of between 250,000-300,000 tons, particularly as they are increasingly at risk from both natural and man-made disasters. But the possibility remains that our descendants may one day accidentally unleash an unquenchable fire.

Emulating the cautionary time capsule tactic that Franny Armstrong employed on The Age of Stupid, Madsen has compiled a compelling tract that consoles and concerns in equal measure. The psychological, ethical and meteorological discussions are informed, but accessible, while the mix of poetry, pugnacity and pragmatism has a quietly devastating power that is reinforced by a largely unspoken sense of guilt at the legacy left by our heedless greed for energy. Simply hoping that history won't have too much cause to judge us harshly hardly speaks well of our supposedly advanced civilisation. But Onkalo seems to suggest that the decision has already been taken to bury our heads in something more durable than sand.

If Into Eternity is sure to spark debate among all ages, Amy Hardie's The Edge of Dreaming is most likely to intrigue fortysomethings suddenly discomfited by the prospect of coming to terms with their mortality. A respected science film maker, with a psychotherapist husband, three children and a large house in the Scottish Borders, Hardie appeared to have a pretty idyllic existence as she approached her 48th birthday. However, a series of dreams disturbed her equilibrium and pitched her into the most difficult year of her life.

In the first dream, Hardie saw her faithful old horse, George, who turned and asked her if she was filming. Disturbed by the vividness of the encounter, she ventured into the night and found that the animal had died of a heart attack in his paddock. Being an atheist and an empiricist, Hardie convinced herself that the dream was merely a coincidence. However, when she was visited by Arthur Howes, her former film-making partner and the father of her teenage son, she became more concerned, as he revealed that she would die before her 49th birthday.

A third dream followed soon after, which seemed to predict that she would perish in a fall from a horse. But it was a persistent cough that was now giving Hardie most cause for concern and tests revealed that she had fibrosis of the lungs, which were only operating at 60% of their normal capacity. Despite suddenly feeling vulnerable and fearful that she would be forced to leave her children when they needed her most, Hardie decided to continue with her film and she interviewed a number of leading scientists and doctors about the biology and psychology of dreaming. She also travelled to New York to see her artist sister, Gwen, who keeps some of their mother's ashes in a pot on her window sill, and consulted Brazilian shaman Claudia Goncalves, who convinced her that she could enter her sub-conscious and alter her dreams and their anticipated consequences.

This is not an easy film to watch and not everyone will be convinced by either its emotional or intellectual discussion of dreams and death. The depiction of cosy domestic bliss is decidedly awkward, while it's difficult not to feel like an intruder during Hardie's medical emergency. Yet, she achieves the sudden shift from personal documentary to scientific study with laudable skill and many of the issues raised by experts like Mark Solms are fascinating (if tackled with necessary superficiality). Moreover, Hardie and editor Ling Lee imbue the action with a poignant poetry through their use of animation, natural history close-up and image manipulation. Consequently, the viewer comes to feel less like a voyeur and more like confidante, who has been invited to share Hardie's most intimate thoughts and experiences in order that they might contemplate and confront their own.

Finally, this week, singing earns 77 under-privileged children from South Africa's Guguletu township the chance to perform on a bigger stage in Holly Lubbock's Fezeka's Voice. Under the baton of tireless teacher Phumi Tsewu, the choristers from Fezeka High School have attained such high standards that they have been invited to sing at Salisbury Cathedral. But rehearsal time is fast elapsing and some of the students have yet to secure their travel documents.

Although the focus falls primarily on Tsewu and his unwavering faith in his sometimes mischievous charges, Lubbock also follows 16 year-old Busi (whose mother dies of AIDS) and 17 year-olds Zukisa and Nokwanda, as they prepare for the trip of a lifetime. Sadly, classmate Thobela has to stay behind because his family is unable to find the paperwork required to support his passport application. Thus, he not only misses the day in London (complete with a visit to Madame Tussaud's and a ride on the London Eye), but also the warm welcome extended by the Salisbury residents determined that the teenagers should enjoy every second of their stay.

News of a family tragedy cruelly intrudes upon Tsewu's triumph. But it speaks volumes for this dedicated and inspirational conductor that he gets the best out of the choir when it matters most and bounces back with redoubled enthusiasm when starting again with a new crop of recruits.