From left: Timothy Spall, Cillian Murphy, Emily Mortimer and Patricia Clarkson. (Photo: Roadside Attractions)

Assembling a dinner party is a bit like putting together a meal: The ingredients need to be the right proportion. In addition to food-and-wine pairings, you want your guests to complement each other, too. If friends famously butt heads, for example, it might be a good idea to keep them apart.

In Sally Potter’s delicious new black comedy “The Party,” the acclaimed English filmmaker deliberately flouts such convention, gathering a cast of smart, veteran character actors — each one embodying a different set of values — and setting them in conflicts that obliterate the line between the political and the personal. This is a film that encapsulates the anxiety of the present moment, complicated by friendships that lean, at times, toward outright hostility.

As the film opens, congratulations, it seems, are in order: Janet (Kristin Scott Thomas), a member of an unnamed opposition party under the U.K.’s Tory government, has just been named shadow health minister. As she prepares a small meal to celebrate with friends, her erratic husband, Bill (Timothy Spall), gets drunk and listens to records. Janet’s guests — each of whom seems to have some secret — include April (Patricia Clarkson), a cynic who can’t hide her contempt for her New Age boyfriend, Gottfried (Bruno Ganz); and Tom (Cillian Murphy), who arrives with a pistol and a stash of cocaine. As for Janet, she clutches her BlackBerry, texting her lover. Inevitably, bitter confrontations ensue, as the dinner guests find themselves rethinking their core beliefs.

Potter’s black-and-white cinematography (a format she has not used since 1997’s “The Tango Lesson”) serves a dual purpose here, recalling the tradition of such classic dinner-party-from-hell tales as “The Exterminating Angel” and “Who’s Afraid of Virginia Woolf?,” where words are used as weapons, and the setting becomes increasingly tense. Also, with the absence of color, viewers can better focus on individual, finely tuned performances. Although the action never leaves Janet’s house or back yard, the camera is always dynamic, framing the actors in unconventional medium shots that are halfway between letting the actors breathe and claustrophobic.

The dialogue — literate without feeling overwritten — begins with an exchange of compliments that devolves into gentle jokes, then mean-spirited ones and finally outright arguments. In addition to Janet’s big news, there are more big announcements coming: Jinny (Emily Mortimer) is having triplets with her partner, Martha (Cherry Jones), while Bill drops a bombshell that is downright shocking. Potter skewers modern political mores by allowing each character to filter these revelations through his or her values — creating a stew of contemporary feminism, identity politics and the age-old clash between radicalism and conservatism. The film’s greatest strength, however, is how each character adapts core values to a changing situation: Even those who appear to be hard-liners are rarely absolutist, surprising us, in moments of duress, with unexpected behavior.


Patricia Clarkson steals the scene as April, whose put-downs land like darts. (Photo: Roadside Attractions)

Part of the thrill of “The Party” is watching the actors bounce off one another. Clarkson is the scene-stealer: April has a dry sense of humor, and her withering put-downs get the biggest laughs. Ganz’s Gottfried could not be more different, with the live-and-let-live tolerance of the free spirit, gently pushing the others apart when they’re at each other’s throats. At first, he seems like a flake, yet his character gradually moves to become the film’s moral center. Other actors — Thomas and Murphy in particular — embrace a more theatrical approach. If their performances seem chaotic or over-the-top, these two nevertheless keep them grounded in a flinty plausibility that prevents the drama from veering into farce.

To the extent that “The Party” has a fault, it lies in Potter’s affection for her characters. Too often, she lets them off the hook, abandoning the exaggeration common to satire. Potter’s cast never overstays its welcome, giving us plenty to think — and talk — about, and in a scant 71 minutes. One thing you can’t say about this party: Unlike at many soirees, these guests don’t need to be told when it’s time to leave.

R. At area theaters. Contains strong language, drug use, hitting and mature thematic material. 71 minutes.