Both types are abundant in Las Vegas, although they are too ordinary to make much of an appearance in Gilliam's film of Hunter S Thompson's drug-fuelled travelogue, Fear and Loathing in Las Vegas. Others have tried before to bring this counter- culture classic to the screen: one early foray had Martin Scorsese directing Jack Nicholson. But now, Gilliam has actually brought it off. His version stars Johnny Depp as Thompson's alias, Raoul Duke; Benicio Del Toro (one of The Usual Suspects) is his lawyer, Doctor Gonzo; and there are cameos by Gary Busey, Ellen Barkin, Lyle Lovett, Harry Dean Stanton, Christina Ricci and Cameron Diaz. Katherine Helmond, the victim of faulty plastic surgery in Brazil, this time suffers the indignity of being metamorphosed into a moray eel.
It is a long time since Gilliam laid down his air-brush and scissors as Monty Python's animation artist. But his vision has always remained graphical. He co-directed the Python films, and made Jabberwocky in 1977. Time Bandits (1981) and The Fisher King (1991) were fantastical voyages of escapism. But his best films have been his darkest: Brazil (1985) is the classic dystopia of Orwell and Kafka, re-imagined with a baroque decor that only adds to the desperation of the trapped individual. 12 Monkeys, his $160m-grossing hit of 1995, is a time-travelling virus thriller. And the films Gilliam has not been able to make say as much about him as those he has: Don Quixote, the Gormenghast books, films based on graphic novels and Phillip K Dick.
All Gilliam's films are about liberty. The make-believe kingdoms and the time travel are only means for exploring it. Hunter S Thompson's book bears a subtitle: A Savage Journey to the Heart of the American Dream; it is a dream, of course, in which liberty is like an incubus. The incursions upon our liberty in Gilliam's films may be technological, bureaucratic, parental or governmental. It doesn't really matter. The resourceful heating engineer played by Robert de Niro in Brazil is a humble superman - not rescuing people in distress, but simply fighting the red tape to get their plumbing working properly. This disdain for regulation improbably puts Gilliam in the same camp as Middle America's anti-government libertarians. "I escaped America and its dreaming in '67, four years before Hunter wrote his book," he says. "I really became very disillusioned. I could just see I was going to have to become like the Unabomber, a full-time activist, or get out."
He got out, and has lived in London ever since. Not that he's exactly wild about all things British either. He expresses contempt for the Cool Britannia concept; culture secretary Chris Smith is "this timid man". He's ambivalent about more Python reunions like the one in Aspen, Colorado, last winter. "The idea of doing a stage show, going on tour, the huge amount of money? It's tired, it's greedy, it's got a few of the guys very excited ..."
And now, with Fear and Loathing, the native has returned. Rooted for once in a real time and a real place (if Vegas is real; but more of that later), the movie seems, for all the drugs, almost pedestrian, when compared to Gilliam's other work. As in the book, there is no real story: only Thompson's psychotic prose, voiced by Johnny Depp. "Almost all the words are Hunter's. We've done that very consciously. We've not tried to `write', but to cannibalise his stuff. There are a lot of ad libs, Johnny was so steeped in Thompsonisms. He spent a lot of time with him and they're totally believable. It became fetishistic. He was wearing Hunter's clothes.
"What seems to work really nicely is this relationship between him and Gonzo. Duke has got a Christian morality floating around in his little heart. And you've got Gonzo, who is truly a pagan force of nature. In some ways, it's Dante's Inferno, but this time Virgil is not a nice calm poet, but this crazed lunatic madman." The film is not so much a road movie, then, as a social documentary.
If the only effect of the film is that people dare once more to smoke in their offices rather than in huddles in the street then Gilliam will count it a victory. "I think the time needs it. Things have become more constricting and confining. Everybody's trying so hard to be nice to each other." Perhaps young people are frustrated by the absence of the obvious "causes" - Vietnam, Civil Rights - which seemed to be around in the 1960s. But who is the 57-year-old Gilliam to lead them? And so nice himself too, his face creased and chipmunk-cheeked from constant laughter, his sweater with some kind of animal gambolling across it. This is not a bitter man.
Terry Gilliam himself grew up in Los Angeles. "I was going to Disneyland every weekend. The craftsmanship was beautiful; the architecture was beautifully done, even though it was silly, fairy-tale stuff. Nobody had ever done anything like that before. I loved it." But he also noticed what it was like outside the fence. "Outside those perimeters, they kind of want to fit in, but it's not lovingly crafted. That seems to be a crucial difference. It has to be well done. All those motels around the perimeter would do really shoddy versions of what Disneyland had done. That was the real world, done by grasping, mediocre people, whereas Disneyland itself was a place that was done really, I think, for the right reasons. It was an act of passion by old Walt. My moment of disillusionment with Disneyland - which was also, I think, in 1967 - was when they started putting ads in the place. And I said ugh, this is like the American Dream we grew up with." But there were perhaps other reasons the dream began to pall. It was on Gilliam's 23rd birthday that President Kennedy was assassinated.
The original Las Vegas had that same magic for Gilliam. "Look at Caesar's Palace. There's the old part of the Palace which has a Deco-esque style to it. It's great because it's abstract, and beautiful, really beautiful. But the newer part which they have recently added is totally literal, the literal recreation of a Roman street, with a sky overhead which changes colour. What's interesting in the design of Vegas is how it's gone from the abstract to the literal. Caesar's Palace is just like Disneyland, with the same sense of detail. But in some of the other places it gets really weird. You start looking around at the architecture and it has no meaning. That's one of the things that got to me about Vegas: nothing has any meaning. Anything could be anything.
"Actually, Las Vegas is a dystopia, except it's a dream of so many Americans. I think the problem is that people don't look at it any more. It's what people dream about, but their dreams are so pathetic and so easily controllable.
"In the book, you start with a banal reality," Gilliam continues. "But then you twist it with drugs into something that's terrifying, like a war-zone. That's what Thompson's doing; he's turning Las Vegas into Vietnam. And we're doing the same thing." To ensure that today's audiences don't miss the subtext, war footage plays constantly on the televisions in every hotel room. Is reality intruding into a fantasy world or fantasy into reality? Whose perceptions are clear and whose are clouded? It would be a mistake to think of this detail as specifically relevant to Vietnam. The artist Richard Hamilton made similar tableaux at the time of the Gulf War, inverting the real and superreal. Other work of Hamilton's around the same time has explored the deracinated nature of typical "international modern" interiors. This provides visual fuel for Gilliam too. "The place fairly reeked of high-grade Formica and plastic palm trees," says the voice-over as Duke and Gonzo infiltrate one of Vegas's more tasteful hotels.
So hideous are these interiors that we see them as if already drugged. The patterns on the carpet and wallpaper along the endless corridors swirl nauseously. The mirrored ceiling accentuates the disorientation. The patterns have been made just that bit too large and garish, and the wide- angle lens that Gilliam uses throughout the film distorts the patterns, making them worse. The film makes only sparing use of digital effects, but occasionally these patterns are brought to life like the plants growing up the walls in Where the Wild Things Are.
Drugs tsars and tsarinas may be disappointed that the film does not make a clinical distinction in portraying the effect of one kind of drug compared to another. Trainspotting, after all, ran solely on heroin. The car Duke drives from Los Angeles to Vegas has a trunk stashed with everything from Adrenochrome to grapefruits. "We spent time originally going through all the different effects of different drugs," says Gilliam innocently, "but in the end we said, f--- it, why bother. Altered states is all it is. I just winged it because I'm actually a surprisingly drug-free individual."
Some scenes are calculated to offend, American audiences in particular. If the white powder that adorns Depp's nostrils for much of the film doesn't do it, then sniffing ether from a soaked American flag ought to. But when we see a hotel bar-room through Duke's eyes, the scene is already familiar from Smirnoff's advertising. Perhaps this is an intentional irony, a comment on the mild-altering drugs that society does permit itself.
It is certainly an intentional irony at the climax of the film when our hero crashes the District Attorneys' conference on narcotics. The camera scans the audience of smoking law-enforcement agents as the speaker rages against "this cancer eating at the heart of America". Perhaps Fear and Loathing is not so much a documentary as a special sort of health-education film.
`Fear and Loathing in Las Vegas' (18) is released in Britain on 13 November.