There have been a slew of such films lately, many of them making their way across the Atlantic from the British Isles -- the latest of which is the grim farce Twin Town. Produced by Danny Boyle and Andrew Macdonald (of Shallow Grave and Trainspotting fame), Twin Town goes for the same kind of hand-colored dreariness and stylized sleaze that marked the Scottish pair's other work. But this film isn't Scottish. Set in a bleak industrial suburb of Swansea, directed by local boy Kevin Allen, and boasting an almost exclusively native cast, Twin Town is very Welsh.

The all-Welsh talent pool makes for an engaging authenticity, but moviegoers will have to keep their ears cocked. Ken Loach's Riff-Raff provided American audiences with subtitles; Trainspotting redubbed some of the trickier accents. Twin Town contents itself with a zany pre-movie public-service announcement explaining that, accustomed as Americans are to a mish-mash of dialect, a bit of Welsh shouldn't bother us. But English is a second language for the Welsh, and unless you're listening carefully, it all might start to sound like "Schouck fratter, will ya."

Don't expect Twin Town to be all Welsh choirs and sheep farmers, either. Like Trainspotting, the film makes a mockery of quaint cultural stereotypes. Wales relied heavily on its coal-mining industry, and, perhaps more than any other area in Britain, has suffered from the process of de-industrialization. This is not the same cozy nation-village that we encounter in Dylan Thomas's A Child's Christmas in Wales. It is a place of disenfranchisement, squalor.

Thomas called Swansea the "graveyard of ambition." One Twin Town character describes it as "a pretty shitty city." Polluted, bankrupt, damp -- Swansea is by no means the jewel in the crown of Wales, and the characters who inhabit Twin Town are not exactly salt-of-the-earth types.

The eponymous twins are Julian and Jeremy (played by brothers Rhys Ifans and Llyr Evans). They are the sort of boys who set decent society ashiver: racing about in stolen cars; snorting, smoking, or gobbling anything that will get them high. Given to meandering philosophical dialogues about nothing, the twins, it seems, have spent so long getting out of their heads that it has become a permanent condition.

They live on a trailer park scattered along the edges of industrial Port Talbot, along with their trashy, dysfunctional family. The setting is archetypally squalid: smokestacks loom on the horizon, the trailer is cramped and chaotic, cigarette smoke and profanity fill the air. For this family -- along with just about every other character in the movie -- "fucking" serves as a all-purpose grammatical device. Fatty (Huw Ceredig), the boys' dad, concerned that the twins will sniff his modeling glue, tells them to "get yer fucking own." The sister (Rachel Scorgie) stamps about indignantly. The mother (Di Botcher) tries to hold the family together with pots of tea. The boys run wild.

It could get depressing -- these are people for whom ambition would seem to have died. But there is also a lively mix of kitsch and color, caustic humor, and even demented affection among the family members. You may find yourself laughing at them, groaning at them, horrified by them, and rooting for them all at the same time.

Yet when Fatty falls off a roof during a laboring job, the shabby idyll is shattered along with his leg. After the accident, the twins pay a visit to "Ponderosa," the home of roofing contractor Bryn Cartwright (William Thomas), to demand compensation.

Ponderosa is a nightmare of tasteless opulence, the kind of home favored by trash with cash. Bryn is a despicable creature, even evil. The twins' visit finds him secretly watching his daughter playing with herself. But the film has fun with him. He is marvelously slippery, full of wet-lipped avarice and lust. Bryn and Terry (Dougray Scott), a bent copper on Bryn's payroll, are the film's most greedily ambitious characters -- and Thomas's damning indictment of Swansea soon takes on special meaning for the pair of them.

When the twins' demand for compensation is scorned by Bryn, the film switches gears. The anti-pastoral motif gives way to themes of revenge, betrayal, violence, and apocalypse -- all within a manic, farcical framework. You find yourself repelled by the nastiness while being drawn in by the smart dialogue and kaleidoscopic imagery. It's awful and it's lovely. Twin Town would have had many a Victorian aesthetician pulling at his sideburns. It turns the old principle on its head, cheerfully insisting: if it's art, it ain't ugly.