Her hunch was amply rewarded. “Secrets & Lies,” which opens the New York Film Festival this week, not only won Blethyn the Best Actress award at Cannes, but the film walked off with the top prize, the Palme d’Or. Three years ago Leigh accomplished a similar double coup in Cannes, when “Naked” won David Thewlis the Best Actor prize and Leigh the Best Director.

Mike Leigh does not make bad movies. It’s an assertion you couldn’t make about even some of the greatest directors in the world (the highest divers are always prone to belly-flops), but I have yet to see a Leigh movie–and I’ve seen most of his 14 features-that wasn’t, at the very least, fresh, brilliantly acted, unformulaic, alive. His movies illuminate the lives of his middle- and working-class characters with an intimacy that can be hilarious, corrosive, embarrassing and deeply moving. His hard-edged humanism disdains glamour and nostalgia-no bridesheads are revisited here. Leigh’s pursuit of emotional truth can veer into absurdism (“High Hopes”), nightmare (“Naked”), social anthropology (“Four Days in July,” which was set in Belfast), withering satire (“Abigail’s Party”) and farce (“Life Is Sweet”)–often all jumbled together in the same movie. In “Secrets & Lies,” which is likely to be his breakthrough film in the United States, painful comedy gives way to something new in his movies-a flood of tears.

It tells the story of a young black optometrist, Hortense Cumberbatch (Marianne Jean-Baptiste), who seeks out her birthmother after the death of her adoptive parents, only to discover that she is white. The mother, Cynthia (Blethyn), is a walking disaster–a needy, mewling, teary-eyed wreck living with her angry daughter Roxanne (Claire Rushbrook), a road sweeper, in a leaky, run-down London flat. But this is no mere excursion into drab, kitchen-sink realism. As the tale fans out to include Cynthia’s prosperous brother, Maurice (Timothy Spall), a portrait photographer married to the compulsive, childless Monica (Phyllis Logan), whose suburban house is drowning in Laura Ashley decorations, it becomes clear that “Secrets & Lies” is less about race than about class, identity and emotional repression. The arrival of Hortense into this wildly dysfunctional family triggers personal transformations that are wondrous, wrenching and crazily funny to behold.

Nothing Leigh has done has been quite so nakedly emotional. But “Secrets & Lies” earns its sentiment, and its embattled hopefulness, honestly. As in all his movies, Leigh elicits fiercely committed performances that keep you hanging on every twitch, snarl and averted eye. In the brilliant scene in which Cynthia and Hortense first meet over a cup of tea, Leigh holds his stationary two-shot for nine riveting minutes as Blethyn, spilling over with ambivalent emotions, and Baptiste, holding in her own primal feelings, come to agonizing first terms with the fact that they are mother and daughter. Bearded, rotund Timothy Spall, a Leigh regular, does something extraordinary with the sad, hardworking, Maurice–he makes ordinary decency thrilling. Logan’s Phyllis comes the closest to caricature (Yuppies don’t fare well in Leigh movies), but just when you think you can write her off she, too, is allowed to stab at your heart.

What’s remarkable about the power of “Secrets & Lies”–and of Leigh’s work in general–is that his unconventional method of making movies would seem an invitation to disaster. For 25 years Leigh has been devising movies, television films and plays (more than 20 of them) that begin with no script at all-just a feeling, an atmosphere, a situation in Leigh’s head. The scenes and dialogue are worked out in close collaboration with his actors in months of rehearsals and improvisations. First Leigh works individually with each principal actor, creating a character’s entire personal history but withholding from him any knowledge of the big picture into which he must fit, so that when he is first thrust into rehearsal with another actor, the interaction is as spontaneous as it would be in real life. “You just act and react as that person would,” explains Blethyn. “One’s only duty is to be honest to this person you’re creating and not try to be clever. If you did try to think of something that wasn’t organic, he’d be onto it in a nanosecond.”

Game playing: Born in Lancashire in 1943, the son of a Jewish doctor (he changed his name from Liebermann}, Leigh has always maintained an outsider’s edge within the English film community. His “organic” methods, arising from his theatrical experiments in the 1960s, made it hard for him to get movie financing. For 14 years all his work was done for television. “It was bitterly frustrating,” says the bearded Leigh, an affable man with a short temper and mournful eyes. “I was told it 20 times: ‘Forget it, you’ll never make a feature film. You’ll never make a film that will work in the States’.” But he won’t think of working any other way. “I don’t read scripts.” And as he has said, he would rather poke steel pins into his eyes than work in Hollywood.

But even Leigh acknowledges that his method can be exhausting. “To be honest, mostly it’s one hell of a damn nuisance.” In the five-month rehearsal process that preceded filming of" Secrets & Lies," Leigh was the only one who knew all the characters! secrets. “This involves all kinds of devices and stratagems,” he explains. “I shot three quarters of the damn movie with the crew under strict instructions not to reveal anything to the actors. It does involve the most elaborate game playing, which a grown-up person can do without.” But when the cameras are rolling, each scene has been set. There’s no improvisation when shooting. The actors never know the whole story until the movie is completed. What emerges in the finished film is remarkably honed and structured: you don’t feel the meandering, actory self-indulgence that often mars American “improvisational” cinema.

Many who saw “Secrets & Lies” in Cannes thought that its uplifting spirit seemed a radical departure from the abrasive Leigh movies of the past. But tenderness has always been part of his range: the intimacy between the working-class couple in “High Hopes” is one of the most convincing portrayals of connubial love on screen. The same razor eyes that captured the scary, woman-abusing Johnny in “Naked” focus here on an optometrist, a photographer and a mother rescued from the blindness of her misery. It’s all in the eyes, and Leigh has great ones.