Danny Boyle's Slumdog Millionaire is the film equivalent of Usain Bolt's performance at the Olympics: funny, shocking, spectacularly turbo-charged. It takes your breath away at the same time as it makes you want to holler with joy or to grab the person next to you: "Yes!"
Loosely adapted from Vikas Swarup's novel Q&A, the film is set in modern-day Mumbai. Like that city, it brims and overflows, chortles with multiplicity.
It creates a scary and beguiling electricity by allowing opposites to collide – horror and joy, colourful fantasy and grimy reality, history and hyper-modernity. It is itself many different kinds of film: thriller, romance, picaresque, a Western stab at Bollywood.
It begins with Jamal Malik (Dev Patel, from Channel 4's Skins), an 18-year-old call-centre chai-wallah, or tea-vendor, fluking his way onto the Indian version of Who Wants To Be a Millionaire? Here, though uneducated, and patronised by the show's host Prem Kumar (Anil Kapoor), he gets through round after round of questions to stand on the brink of winning the top prize.
No one can believe Jamal's success, though; he represents an India obscured by recent cheerleading about that country's growing affluence and middle-class swagger. He's seen as dirty, virtually untouchable.
Kumar, in a fit of pique, has local police officers headed by Irrfan Khan torture the young man. How, they want to know, pounding and electrocuting him as they interrogate him, can an upstart like him possibly know the answers to the TV show's questions?
And so, in a piece of plotting both nimble and schematic, one that involves lots of dramatic flashbacks, Malik reveals to the officers the train of events by which he amassed all sorts of facts.
He can answer a question about film actor Amitabh Bachchan because when he was younger he had dived into a public latrine in order to get the Bollywood legend's autograph. He can answer a question about a gun inventor because he'd heard the name "Colt" mentioned as he was helping his brother Salim to rescue fellow orphan Latika from the clutches of brutal pimps.
A fragmented biography emerges: he's a shanty-town urchin, born to a mother who's later slaughtered in an anti-Muslim pogrom, and forced to hustle a living that takes him on adventures both abysmal and exciting through a society that is becoming flashier and more urban as time goes by.
The narrative structure of Slumdog Millionaire is perfect for a restless director like Boyle, allowing him to fast-forward between dramatic episodes at will, and freeing him from the need to dwell too intimately on the finer shades of characters' personalities.
He's always been a moviemaker keener to play with form and tweak with tempo than to explore the complexities of human psychology. Yet the film, which for all its breathless intensity rarely subverts our expectations, and which in its final section sticks closely to the conventions of modern action drama, never fails to grip or to delight.
It's easy to sense the excitement that Boyle – and his cinematographer Anthony Dod Mantle – felt when shooting in Mumbai. They're alive to the jagged rhythms of the city, its palette of colours that are quite as rich and surreal as any in Trainspotting.
The metropolis, at once deranged, grotesque and magical, embodies all of Boyle's signature motifs – the amorality of Shallow Grave, the mob mayhem of 28 Days Later, the enchanted child's perspective of Millions – and renders them even more vivid.
As such, Slumdog Millionaire strikes me as a hugely important film in contemporary cinema. It's an advertisement for the dramatic potential of the non-Western city. Mumbai, Chennai, Shanghai, Lagos: they, not New York or Los Angeles, over-familiar and culturally declining cities both, are where any writers and directors should be heading today. They offer more energy, extremity, humanity – fillips to the imagination.
Sure, there are risks involved for those who elect to make that kind of creative migration. These days any film set in a poor or developing nation will attract scrutiny.
What we now call the Third World was patronised or ignored by moviemakers for much of the 20th century; it's no bad thing if their successors are forced to think more deeply about what they're doing.
Especially when, following the success of City of God, a cinematic sub-genre – let's call it ghetto picturesque – has developed so that, in films like the (marvellous) Bourne Ultimatum, poor neighbourhoods full of veiled women, market stalls and bearded elders feature as little more than gritty wallpaper, edgy backdrops across which hurtle maverick agents and secret-service free runners.
I've heard it said that Slumdog Millionaire itself is patronising, that it doesn't say enough about imperialism, that it prettifies suffering and poverty. To which I can only say: nonsense.
Boyle is not a political director, but his film is incalculably more radical than the glossy, blinged-out pictures that emerge every week from the studios of Mumbai. His screenwriter is Simon Beaufoy, best known for The Full Monty, also a portrait of economically ravaged underdogs trying to make a life for themselves.
Their collaboration here is a tricked-out, kinetic throwback to the crowd-pleasing, emotionally intense social dramas that India excelled at during the Fifties and Sixties, epic sagas in which young men, impelled by a hunger for justice and believing in a better future for their nation, fought against local gossips, corrupt moneylenders and predatory landlords.
Indian directors rarely make those movies these days; good on Boyle for trying to do so.
The film wouldn't be half as moving were it not for Dev Patel. He's a little hesitant and muted at first, but refines a melancholic heroism that soon becomes very winning.
We feel like whooping as his character rides on top of railway carriages, escapes from Dickensian villains about to blind young children in order to boost their begging potential, risks everything to win the love of his beloved Latika (Freida Pinto).
Slumdog Millionaire is as acerbic as it is clear-eyed about the brutal power dynamics in modern-day Mumbai. But, at the same time, what makes it so warming and what has been inspiring audiences all across the world to cheer at its rousing ending, is its passion for a place that writer Suketu Mehta has described as a "maximum city".
Mumbai has been through hell recently. But Slumdog Millionaire, whose everyman hero is a Muslim, is a wonderful tribute to it and to its people. It is, in fact, a maximum film.
