Nobody takes “class war” more seriously than the Brits.

A nation that misnames its most exclusive institutions “public,” where accent, political party and the very newspaper one reads seems set for life at birth, it has to.

And in acknowledging this, it’s remained a step above the U.S., where “class war” is an accusation the side with all the resources convinces the side with few that their gripes about “the one percent” have no merit. And a lot of the fools buy it.

From its opening “moment of despair” analogy about sociological experiments carried out on drowning rats, to all the slang, sarcasm, wit violence that follows, “Us and Them” is a violent, profane British satire of the conflict.

It’s like Guy Ritchie got political instead of marrying Madonna.

Glen, “the wrong sort,” is introduced to girlfriend Phillipa’s family, luncheon at their gated country estate. And it doesn’t go well. Working class Glen (Jack Roth) is confrontational, and out of his element.

Phillippa (Sophie Colquhoun) tries to keep the peace, or so it seems. Her keeping-up-appearances mum (Carolyn Backhouse) is polite in spite of everything.

But bank dad Conrad (Tim Bentinck) isn’t hearing Glen’s uncouth “We’re gettin’ married.”

“Do you see my car (a 1970s Rolls Royce in the driveway)? It’s a classic. And the reason it’s a classic is that it has a heritage.”

“That car is rather like my family. It has tradition, value and a heritage…made over generations.”

Over his dead body you’re marrying his daughter, in other words.

“You think I’m not good enough?”

“Think you’re not good enough? I KNOW you’re not GOOD ENOUGH!”

And that’s when not-actually-Glen plays his card, the associates with guns and a video camera show up, and his own lecture is trotted out.

“It’s called ‘class war’ for a reason! There has to be victims on both sides!”

What follows is a punk-rock-scored generally brisk, often witty, violent and cruel dose of class “payback,” administered by an off-his-nut anarchist and his two more pragmatic running mates.

Writer-director Joe Martin takes a lot of pacing, editing and joking cues from the “Snatch” and “Lock, Stock and Two Smoking Barrels” era Ritchie, usually to great effect.

The tale is told with flashbacks and flashbacks within flashbacks, chapters headed “Complications” and “Last Chance” and “What Phillipa Knows” titles. An incredulous mention that this manse has “seven toilets” prompts a montage showing them set the “The 1812 Overture.”

Tying up a posh earns a “Seriously! I’ve just had this shirt STARCHED!”

Danny (Glen’s “real” name) lets his idealistic grievances show in every (usually profane) word to come out of his mouth. He’s going to “expose the wealthy to the same threats we face…Remember, there are more of us than them.” His lectures about criminal bankers escaping the “justice” of “the market” that they laud as “king,” until they’re the ones needing the bailout, sting.

“You’re terrorists.”

“Depends on how you look at it.”

In his mind, Conrad delivers his side of the “debate” in a tirade directly to the camera.

“You bath-dodging, benefits-scrounging, joy-riding, track-suit-wearing, white-van-driving, ketchup-and-chips-with-everything eating, ‘soap’ watching…product of a teenage mother and an absent smackhead father…sixth form Socialist mongrel.”

Back atcha, “You ski-holidaying, horse-riding, fox-hunting, money-grabbing, tax-dodging, back-slapping tie crest” insert the favorite Brit-cockney swearword here.

Bentinck and Roth make well-matched sparring mates, overshadowing but not smothering strong supporting performances by the accomplices (Andrew Tiernan and Daniel Kendrick) and the lady hostages.

Like good satire, “Us and Them”  burns, bites and wounds as it lands its punches. Like stumbling satire, the tone feels off as writer-director Martin lets things go too far even as Danny’s mates start to absorb his message.

Still, a darkly-fun working class venting at an increasingly unjust casino game that is stacked entirely in one side’s favor — for now.

MPAA Rating: unrated, violent, profanity

Cast: Jack Roth, Sophie Colquhoun, Tim Bentinck, Carolyn Backhouse, Paul Westwood

Credits: Written and directed by Joe Martin. An Orchard release.

Running time: 1:23