There will always be an England, and as long as there is, let’s hope there’ll be someone like Frank Oz to wind its snooty crank. The director falls back on that very particular kind of farce in “Death at a Funeral,” in which an unexpected onslaught of rude calamity wreaks havoc on social decorum, each successive new outrage further stripping away the façade of civility.

Set at a memorial service for a beloved Great Man, the film offsets the somber propriety of the occasion with the frantic machinations behind the scenes: the nerve-wracked good son, played by Matthew MacFadyen, whose noble, self-effacing efforts to do the right thing are repeatedly profaned by circumstances that spin ever further beyond his control — as relatives, friends, and a mysterious stranger pour into the family estate. The ensemble approach allows for a maximum of comic scenarios to be put into effect, as the film’s motor revs into higher and higher gear. Expert pacing and delivery, as well as the abundance of hyper-articulate, over-educated, effervescently British character types, ratchet up the cringe factor accordingly. The groan-worthy gutter humor that went splat in the recent “The Ten” busts guts in this tea-and-crumpets milieu precisely because the humiliation counts for something.

As the extended family gathers for the funeral, a number of factors come into play. The most spectacular concerns a young woman hoping to smooth over tensions between her disapproving family and her husband-to-be (Alan Tudyk, last seen in “Knocked Up”). She accidentally pockets a bottle of her deadbeat brother’s homemade hallucinogens, thinking them to be mild sedatives, en route to the funeral. Then she makes her beloved pop a few to calm his nerves. Before long, he’s bugging out, guffawing at inappropriate moments, weeping at others, and, after disrupting the service in a paranoid fit, finally strips off his clothes and ascends to the roof — dashing every desperate attempt to hide his condition and just get through the afternoon.

As a comic performance, it’s sheer bravura, and not in that hammy, awful, yammering manner of Jim Carrey. Mr. Tudyk embraces the moment as if a thousand butterflies have been released from his soul, going all star-child as his prospective in-laws gaze in horror and his fiancée wonders if this is, indeed, the proper moment to announce that she’s pregnant. It’s a beautiful thing. And it’s not the only revelation in a day when forbidden family secrets are exposed — not even by half.

Meanwhile, the pills have been left somewhere and no one can find them. But they will, they will. All this becomes oddly significant when that mysterious stranger turns out to be a persistent dwarf (Peter Dinklage, whose profound sense of dignity strikes the perfect note), who brandishes some very candid Polaroids of himself with the dearly departed, suggesting the man enjoyed a much fuller life than his sons ever imagined. What to do? While Mr. MacFadyen’s increasingly frazzled character contends with this question, bringing his best-selling novelist brother (Rupert Graves, strutting like a rock star) reluctantly into the fray, Mr. Oz unleashes an episode of scatological humor that involves a cranky old uncle, wheelchair-bound, whose bowels are in an uproar.

That the screenplay can actually riff on this situation as long as it does is fairly amazing. But it’s even more amazing that all the film’s absurdist tangents suddenly converge into a single, practically symphonic moment of black comedy, made even funnier because the audience has been able to follow its steady, inevitable escalation.

The film’s antic disposition, or rather its disposition toward antics, may strike some as an exercise in overkill, even though, curiously, the film disappointingly resolves all the comic trauma by letting everyone off the hook. Moreover, a lot of the material, especially the closeted-gay jokes, seems dated. But for Mr. Oz, finger-snap pacing and an expert cast (surely familiar to any BBC America viewer) bring this “Death” to giddy life.