But are you happy?

Happy-Go-Luckyis one of Mike Leigh's cheerier works, and een the famously dour director seems to have lightened up. He tells Donald Clarkeabout getting on with life, keeping secrets from his cast, and the real reason Abigail's Partywas a success.

MIKE LEIGH does not, they say, "suffer fools gladly". This cliché is, of course, generally used about people with the manners of drunken Visigoths. Look at them sideways and expect to get an arrow through your head.

Over the last four decades, a fair number of journalists have, indeed, emerged pale and shaking from interviews with the English director. Ask the wrong question concerning his peerless oeuvre - films such as Naked, Secrets & Liesand Vera Drake- and you can expect a scowl and a casting of eyes to heaven. Ask about his private life and you had better don body armour.

Happy-Go-Lucky, Leigh's latest comedy, received its world premiere at the Berlin Film Festival only days before we meet. But I sense he is already beginning to tire of one particular line of questioning. The picture, which follows an effervescent primary school teacher as she bumbles about south London, appears to showcase a lightening in Leigh's tone. After all, Vera Drake, his previous film, could not have been more depressing.

"I suppose my films do deal with aspects of how we cope with the world," he says. "But things are never as simple as that. The idea that I will make a jolly film when I am happy or I'll make Vera Drakeif I'm miserable is nonsense. Vera Drakedealt with a very specific issue - abortion before the 1967 act made it legal - and I had been thinking about that theme for years."

As it happens, 65-year-old Leigh is all charm today. That is not to say he looks cheery. Burdened with the collapsed features of Droopy, the cartoon basset, the director is, I would suspect, physiognomically incapable of radiating any inner bonhomie. It is, thus, not altogether surprising that critics examine his films to gain clues as to his current state of mind.

For good or ill, Happy-Go-Luckybelongs to Sally Hawkins. The actress makes a tireless whirlwind of Poppy, the central character. While her driving instructor goes insane, her pupils squabble violently and her sister sinks into grim suburbia, Poppy remains optimistic and energetic. For all its sadder moments, Happy-Go-Luckyis, well, a happy film.

"I think there is an interesting set of ideas here. On the one level, here we are in the 21st century and we are destroying our planet and knocking lumps out of one another. This is not the world we who began working in 1970 would recognise. If you'd said to us that, in 35 years' time, the world would be in the grip of violent religious mania, we would have said you were crazy. But, despite all that, there are still people like Poppy getting on with life."

Like all Leigh's films, Happy-Go-Luckywas developed through a process of improvisation. Despite the involvement of dozens of actors through the decades, the director's films do keep returning to common themes and characters. Poppy, in particular, is a very recognisable figure from Leigh World. Like Alison Steadman in Life is Sweet, Imelda Staunton in Vera Drake, Lesley Manville in All or Nothingor Brenda Blethyn in Secrets & Lies, Hawkins plays a long-suffering good egg on whom weaker and more morally flawed characters repeatedly lean.

"I'm sure you can see that link," he concedes. "I find it difficult to isolate one character from the others in my films. They only exist as defined against each other. The title of the film is not, I think, ironic. She is happy. She is not delirious like somebody on mushrooms. But, yes, she is a happy person."

Mike Leigh was born and raised in Salford, Lancashire (allegedly the model for Coronation Street's Weatherfield). Despite being the son of a doctor, he has always denied that he had a middle-class upbringing. His dad was, he says, always chasing up debts, and luxuries were rare. He fancied himself an actor and won a place at the Royal Academy of Dramatic Art, but realised his talents lay elsewhere. After a spell at London Film School, he set about writing and directing his own plays.

He got to direct his first film, Bleak Moments, just as the British film industry was about to go into hibernation. This was 1971, and, like a number of his contemporaries, he was forced to move into television for the next decade. During that period, he honed his unusual talent and delivered such mordantly brilliant plays as Nuts in May, Kiss of Deathand, of course, the timeless Abigail's Party.

Does he regret being forced into television? "That is a very interesting question," he says. "If you had asked me then I would, undoubtedly, have said 'Yes'. For a decade, in between Bleak Momentsand our return to features in the 1980s, I spent the whole time being pissed off. Can't we shoot on 35mm? And so on.

"But in hindsight, I was wrong to be annoyed. It was a very rich and productive period. We did all this good work that helped us mature and, when Channel 4 came along and allowed us back into film, we were, I think, well prepared."

Of all the fine work Leigh delivered for television, Abigail's Partyremains the most durable. Featuring Alison Steadman, then the director's wife, as Beverley, the hostess from Hades, the play has come to define a certain class of 1970s kitsch.

Cheese'n'pineapple nibble, anybody? "It was originally a stage play, of course," he remembers. "But then Alison Steadman became pregnant - with somebody who is now a 30-year-old graphic designer - and we just about had time to do it on television. When it was screened, a second time there was a strike on at ITV and a highbrow show on BBC2, so it ended up with viewing figures of about 16 million. It just passed into another dimension then."

Despite the success of Abigail's Partyin 1977, it took another six years for Leigh to get a feature film into cinemas. Since then, however, his movies have become a constant feature of the cultural environment. David Thewlis's performance in the grim Nakedsecured the top acting prize at Cannes in 1993. Secrets & Lieswon the Palme d'Or three years later. Vera Drakewas nominated for three Oscars in 2006.

Despite delivering defiantly eccentric work, Leigh has never found himself idling. What's the secret? "The truth is I have been remarkably lucky," he says. "It should have been impossible to do so many films with no script to show a producer. I have a fine producer in Simon Channing-Williams and, most importantly, the way I work, you either give us the dosh or you walk away. Nobody gets to interfere. Nobody gets to muck them up. So the films are never interfered into oblivion."

Does he ever get tempted to change methods and take on a more commercial project? "No. What would be the point? You know, for me the work is like one great continuous movie." The Leigh Meta Movie. Long may it continue.

Happy-Go-Luckyopens next Friday

The Mike Leigh method

EVER SINCE Mike Leigh moved into film and TV, he has developed his films through a process of improvisation.

"It's a standard procedure with every film," he explains. "With every film I make, certain information is held back from every actor. The deal is they will only ever know what their character knows. So you hold stuff back until it is useful for them to know it."

For example, in Vera Drake, (starring Imelda Staunton)  the actors playing Vera's family did not know that she was an amateur abortionist until late in the rehearsal process.

"That allows them to be organic and truthful within an exploratory process," he says. "Mind you, the process has changed over the years. It is changing all the time. It is becoming more complex and sophisticated. In Happy-Go-Luckywe had to develop scenes that take place during the character's driving lesson.

So, I was squatting in the back seat with a notebook. Very uncomfortable when you hit a speed bump."