Parents are up in arms about 'Bad Santa' and its 15PG rating. Its star Billy Bob Thornton tells John Patterson about playing Santa drunk, swearing and urine stained.

Awarning: as Liveline listeners realised to their disgust last week, Billy Bob Thornton's new film, Bad Santa, is not Miracle On 34th Street. It isn't White Christmas. It isn't The Snowman. No, no. It's the first Christmas movie for people who flat out loathe Christmas. The title says it all. Here Santa is a criminal, a safebreaker, a thief, masquerading as Saint Nick at a particularly alienating and depressing mall in Phoenix, Arizona, that he and his black elf partner in crime (played by a boisterously tiny Tony Cox) plan to rob come Christmas Eve.

And he's a drunk. Not of the merely pissed-at-work type but of the unsalvageable-soak variety, sitting in a urine-stained red Santa suit as he dishes out prezzies, and forever looking around for something to throw up into or for a windscreen to smash with his empties. He's no fan of children, never bothering to moderate his splenetically obscene manner of speaking when they're around. Come to think of it he's not wild about their parents, either, unless he finds a mother of the right bulk who'll permit him to sodomise her in the changing cubicles (and there are takers).

This, after all, is Terry Zwigoff's America, and as Bad Santa's star, Billy Bob Thornton, tells me, the director of Crumb and Ghost World "in a lot of ways is Bad Santa. It was almost like he was directing a movie about himself. He just doesn't believe in this society. But you know, these days, who does?"

Bad Santa is for those of us who remain sceptical. It is, be warned, a powerfully aggressive, scatological, foul-mouthed and very in-your-face rant against all the rubbishy, tinsel-covered, market-oriented fakery of the holiday season. In the US it was the biggest comedy hit of last year and a critical success too. Its backers have geared up their publicity machine all over again to launch the film properly here at the appropriate seasonal moment.

Knowing that Thornton has been dragged out to do the whole junket/ round table/media circus rigmarole all over again, I wonder just how happy he'll be after spending a day and a half in an anonymous hotel suite, fending off questions about Angelina Jolie from celebrity-crazy Euro-hacks. The first sight of him isn't encouraging: he sho' 'nuff didn't spruce himself up this morning. Sitting alone at a small table in a bare room, he's dressed in the sort of sleeveless plaid shirt favoured by the redneck in the roadhouse bar who'll kick your ass just to pass the time. Jailhouse tattoos stain his bare arms, he's sporting a narrow chin beard and he's smoking in front of an overflowing ashtray. His greeting is interrupted by an explosive hacking cough, versions of which will recur as deafening percussive pops on my tape recorder.

But Thornton's a southern boy, and that means he's a courtly type, standing up to shake hands and making sure you're comfortable before we proceed. Turns out he's proud to be out pushing Bad Santa all over again and pleased with its success. "It's a good one. It's funnier'n shit. I think people wanted to see something they'd actually laugh at, free to be not so constrained in the holiday time, because, you know, a lot of people don't even like the holidays. At the end of the day it's not just a movie that's for shock value, to be cynical. It's got basically the same message as any other Christmas movie does, it's just . . ." - and here he issues that wide sneer cum beaming smile that's one of his most potent actorly weapons - "it's just executed differently."

Thornton, like his good friend Bill Clinton, was born in Arkansas - in 1955 in Hot Springs, once a wide-open town where the big gangsters of Chicago and the upper midwest came to cool their heels come subpoena-and-grand-jury season. It's calmed down a little since its notorious heyday. "See, gambling was abolished in the late 50s or early 60s," he says. "I was just a little kid when they abolished gambling there, but I was old enough to remember people pulling handles and stuff. What they still have there is Oakland Park. Big race track. And they still got the strip joints."

Thornton is the most visible and talented actor of southern extraction working in Hollywood, and where he's from is hugely important and invigorating to him. All his greatest achievements as a writer, director and actor have their roots in and derive their vitality from his strong sense of regional pride. Not that he's a southern chauvinist of the Confederate-poseur variety; he's just anxious to explicate its complexities and its contradictions intelligently, and he takes very seriously what he sees as an obligation to depict accurately the place that made him.

Is the south a sort of shadow America, I ask, a parallel universe? "Yeah. I think it's the soul of the country. I used to do a one-man show, and the first thing I'd say was: 'Y'all probably think I grew up screwing my sister. But all the time you're putting us down, remember this: Look around and you see how many presidents were from the south, how many authors we studied in school are from the south, and if you want your heart operated on you better go to Houston. And you wouldn't have any modern music if it wasn't for the southern half of the United States. So next time you're out there, bumpin' your asses together on the dancefloor, remember that if it wasn't for the south you'd be listening to polkas and classical music.' " Is it galling to be patronised outside the south? "We get the same shit. For us it's like what Arkansans are like to people in California, is what people from, I dunno, Liverpool are to Londoners. Looked down on as dumb, working class, not educated."

One thing he really hates is the way non-southern actors seem to overwhelm south-themed movies with godawful Grand Ole Opry accents. Steel Magnolias must have been awful for him to endure. "Oh, a f***in' nightmare! But also imagine how I felt when there was an English director, an English actor and Australian actress doing a story of the civil war - filming in Czechoslovakia! I was just, like, are you shittin' me?" He is referring, of course, to Cold Mountain. "I've never seen it. I won't see it, and simply because if I called folks up in England one day and said, 'Hey, I wanna play Benjamin Disraeli,' they'd tell me I was full of shit and kick me out the door - and they'd be right!"

I notice that his tone doesn't become louder as he warms to his theme; he just calmly triples the number of punctuating expletives. And although he's friends with Anthony Minghella, and likes his other work, he seems determined never to let the film's title sully his lips.

"But let's say they did a movie about the Battle of Britain, and all the guys flying those planes are, like, let's say they get me and Gary Sinise and John Malkovich and Robert Duvall, well, there'd be an uproar. But then you get a situation when it's reversed, with English directors and actors doin' a movie about the civil war. Goddamn! I got relatives who died in that f***in' thing.

"There's a bunch of southern actors who could have been in that thing and made it so real it would have chilled you to the f***in' bone. But these days they gotta get whatever's glossy at the time and use it for all it's worth. Plus they shot it in Prague! I mean, goddamn, if you wanna see pretty country go to South Carolina!"

A pause, a fresh cigarette, some more blat-blat hacking. "Oh, I'll probably get in shit for sayin' all this stuff. And I'm off to England on Friday!" But Hollywood itself is really little better when it comes to southern stories, as Thornton explains when he describes the hassles he's had over the past 15 years trying to finance a biopic of the country singer Hank Williams, the original Cadillac cowboy, ur-hillbilly, and a name still uttered with awe south of the Mason-Dixon Line.

"We actually pitched it at a major studio, to this lady executive. Andshe said she didn't really think they were that interested in a baseball movie! And I said, 'I think you may be confusing him with a couple of ball players, Hank Aaron and Ted Williams. Actually, Hank Williams was not only a great country singer, he was the original tragic pop star, and if you're gonna make that story you have to make the Hank Williams story.'

"They'll do it about Jim Morrison, and why the f*** make it about him, because Hank Williams lived and died that story years before Jim Morrison, way before? I mean, in the south you wouldn't have these guys without Hank Williams. I dunno. Hopefully, we'll get that off the ground some day - and I think the person who should play him is his grandson Hank III. He'd be perfect."

I suggest that as a southerner in Los Angeles, as a red-state kid with a quintessential blue-state job, the cultural divide in the US must run right through the centre of Thornton's head. "The politics right now are so messed up here I hardly know what to think. We've had a bad time recently. And America's going to f*** around until the whole world really does hate it. They talk about how people hate it right now, but the potential for how bad we could be hated is really not good, and if we don't watch our ass we'll lose it altogether."

As I shake hands to leave he casts an eye out the wide window of the 15th-floor suite, where grey skies growl all the way to the horizon. "First rain in 183 days, I heard. I can't get enough of this, can't wait to get to London." And then he muses again. "What's funny about England and its involvement in this Iraq-war thing is that we've watched you have the same guy in there with both these presidents. It's like Blair's there with Clinton and then Blair's there with Bush. They always say that England does whatever America does, and a friend of mine joked that Blair even had heart trouble when Clinton had it!" Always leave 'em smiling: it's a southern thang.

Bad Santa is on general release

Guardian