If British life seems to be a miserable, heaving sea of gloom in many of Mike Leigh's films, think of Leigh as an undaunted pearl diver.

Of course, this would be very metaphorical: Mike Leigh, a bearded, 59-year-old director from Manchester who made "High Hopes," "Life Is Sweet," "Secrets & Lies" and "Topsy Turvy," most certainly doesn't go plunging into oceans.

But in his films, including "All or Nothing," which opened last week, his sensibility dives into the existential bleakness and resurfaces with surprising discoveries -- subtle little insights for us as we sit there in the dark.

Here's a moment of hope, or there, a comment of immense vulnerability. Perhaps someone's smile (including Leigh's in interviews) can suddenly break through and light the darkness. And in "All or Nothing," a family can realize love was always there. All they had to do was reach for it.

But that family lives in a depressed South London housing estate. And for most of the film, they seem to be spiraling down into the worst of circumstances. Many of their neighbors are in similarly dire straits -- some loveless, others dour, just about everyone in some sort of emotional pain.

"All or Nothing" isn't "Singin' in the Rain."

Leigh spoke about his film at last September's Toronto Film Festival and in a recent telephone conversation from London. He bristled somewhat when it was suggested the movie might be construed by some viewers as unrelentingly grim. If there's one thing Leigh does without fail in interviews, it's to question the premises of questions and what he often calls "woolly thinking."

"I think it's a simple view, a narrow view," said Leigh. "I don't see it as unrelenting grimness. I think these characters' lives are far too complex. It's obvious they're incomplete, sad, and that is grim in some ways. But I see the film as a whole. It's a complex tapestry of humanity, I would say, really. There's sadness, a grimness, but there's also humor, love and violence, and you know, miscommunication, all kinds of stuff going on."

In the movie, Phil Bassett (Timothy Spall) is a taxi driver who seems to have given up on life. He gets up late. He begs his own children for money. And he pays little attention to his long-suffering, hard-working wife, Penny (Lesley Manville). She, in turn, feels their romance has long since run its course.

Their children are challenges in different ways. Rory (James Corden) is a miserable, overweight teenager who communicates by yelling and spends most of his time in front of the telly. Rory's sister, Rachel (Alison Garland), who works as a cleaner at a senior citizens' home, is almost painfully withdrawn.

"Sure, Phil's a very sad guy," said Leigh. "And sure, you could describe this as a grim picture, but within it, what's important is the sense of his wasted potential, and his ability to see things and understand things from a philosophical outlook, despite his situation. And yeah, the kids are aggressive, but they're vulnerable."

Leigh also cited Maureen, another character in the movie (played by Ruth Sheen), who jokes her way through life, despite an oppressive home life. On Saturday nights, she loves to go out and sing karaoke.

"Here's a woman having as tough a time as anybody, and she deals with it and has a sense of humor about it. And when she stands up and sings, it's part of the celebration of life."

"All or Nothing," Leigh summed up, "is not an exercise in bleakness or aggression, it has many more colors on the palette than that. . . . If the film's about something, it's family. All of my films are, in some way, about family."

Indeed, family connections -- or their screaming absence -- factor in all of his works. In the 1996 "Secrets & Lies," a black woman searches for her birth mother after her adoptive parents die. Her biological mother, she discovers, is white.

Even in "Naked," a 1993 film about the emotionally tortured world of a hyper-intelligent apparent misogynist, it's the central character's family history that defines his actions.

Critics have routinely lauded Leigh's films. And at the Cannes Film Festival, "Naked" won awards for Leigh's direction and David Thewlis's lead performance. "Secrets & Lies" won the Palme d'Or and the acting award for Brenda Blethyn at Cannes, plus five Oscar nominations and numerous critics' association awards.

A distinctive feature of Leigh's films is the keenly observed acting. Compared with the characters in a Leigh film, those in other movies suddenly seem like airbrushed, overpolished abstractions, created entirely for the audience's comfort zone. Leigh's characters are so unguarded and honest, you feel as if you're watching a documentary. And yet those performances are clearly not "real." In their own, intense, British way, they are also stylized.

"My films, at the end of the day, are a heightened distillation of reality," said Leigh. "And without trying to sound pretentious about it, I would submit that these characters are universal."

Leigh has developed a singular collaborative method with his actors, which he started in the early 1970s as a television director. (He made eight full-length films for British television.) He makes his cast rehearse for weeks and even months (five months for "Secrets & Lies") before the cameras roll.

At first, each performer works exclusively with Leigh, exploring possibilities and directions for his particular character.

"There's a strict code of privacy," said Leigh, "in which actors are instructed not to share their backgrounds or biographical information with one another."

"Huge amounts of what we do," Leigh told Salon.com in 1996, "never sees the light of day in tangible terms, as action in front of the camera. But we really know who these people are. We know everything there is to know about them socially, economically and in every detail of their lives. And it all informs what happens."

Only after everyone has evolved their roles to a satisfying level, Leigh continued, does he bring the performers together. The cast then improvises scenes, with Leigh taking extensive notes. And little by little, the story evolves. And a script is finally written.

Leigh has worked in this manner with such performers as Tim Roth, Gary Oldman, Blethyn, Jim Broadbent, Thewlis and his former wife, Alison Steadman. Many, including the last four, are frequent collaborators with Leigh.

From these collaborations, enduring friendships have grown. One of Leigh's most beloved performers, Katrin Cartlidge, died in September of complications from pneumonia. And Leigh was busy at work creating a compilation of her film performances (including leading roles in "Naked" and another of his films, "Career Girls") for a special memorial service at London's Royal Court Theatre on Nov. 10.

"People that work together and share a creative experience become very attached to each other," said Leigh. "And certainly Katrin was part of that. But it ought to be said, Katrin was part of all sorts of families. She was very much everybody's friend."

Working with Leigh, recalled Manville, who accompanied Leigh to Toronto, "you become very involved. It's not that normal feeling [working on other films] where you just turn up, hopefully having got a character and a performance together by yourself, and if you're lucky you'll get some direction. With him, it's totally one to one."

Manville was the first performer to work with Leigh on "All or Nothing." At that stage, she said, "Mike told me, 'We can cast the net as wide as we like. I've got no preconceptions about where this thing will go.' . . . Certainly he had in his head that the film would be about the difficulties of life and love, and getting through life without love. But it could have been set anywhere and they could have been any class. Eventually we decided, between us, that [Manville's character] would be working-class from a pretty poverty-stricken area of London, where getting by each day was a struggle."

Spall, also on the Toronto trip, has worked "six times in 21 years" with Leigh and, like most of Leigh's troupe, has become a friend of the director's. "Sometimes if you get friendly with someone, it's difficult to be told what to do by them, or led so assiduously by the nose through the technique -- this science he's invented to achieve what he does. Although you'll have more input than you'll ever have [in other acting roles], you still can't move without him. So it's a very strange contradiction in a sense."

Said Leigh of his process: "The contribution of the performers in my films is huge. Each actor has much more of a stake in his or her role than they often do in other films. And they've contributed to those characters, no question. But having said that, these characters are absolutely my creations."

Mike Leigh on the set of "All or Nothing." "If the film's about something, it's family," he says of his latest.Mike Leigh with British film awards for "Secrets & Lies," above; and a scene from his latest, "All or Nothing."