BERLIN - To briefly compare two comedies that have no obvious points of comparison whatsoever, "A Long Way Down" gets precisely one thing right that "M*A*S*H" does not: suicide is not painless. Not for viewers of the former, at any rate, as each mirthless minute of Pascal Chaumeil's wretched suicide-club farce prompts a fresh and previously unfamiliar grimace; rarely has such a comic premise been so exhaustively milked, as if to perversely prove its breathtaking lack of potential. "Still not laughing? Good. Now, try this cerebral palsy joke!"

The list of subjects that can't be made funny in the blackest of comedy contexts is an increasingly short one, and suicide is certainly not on it -- as "Harold and Maude" so gloriously proved in 1971. But just as there's human truth in absurdity, bad taste requires an awful lot of good judgment; not having read it, I don't know if Nick Hornby got the balance right in his divisive 2005 novel, but it certainly hasn't been flattered by Chaumeil and screenwriter Jack Thorne's cloth-eared screenplay, which alternates between hooting at its cartoonish quartet of end-of-their-tether characters and treating their largely ludicrous issues with patently disingenuous sentimentality.

"A Long Way Down," then, centers on four otherwise disparate individuals who meet by chance one New Year's Eve on the roof of a London tower block popular with locals looking to plunge to their deaths. After dissuading each other from jumping, they resolve to hold off until Valentine's Day instead, forming an emotional support group in the meantime.

You'd do the same, of course. Who wouldn't want the emotional support of Pierce Brosnan's disgraced TV presenter and convicted statutory rapist? (This BBC Films production could hardly have come along at a worse time: following the recent Jimmy Savile scandal, asking the audience to engage with a fictional celebrity who admits to having slept with a 15-year-old is, well, optimistic.) Who wouldn't delight in the company of Imogen Poots's spoiled, drug-addled politician's daughter, or Aaron Paul's embittered rock star turned pizza-delivery guy? Clearly not Toni Collette's sweet, sad-sack mother of a CP-afflicted son, who gratefully takes up with all three for reasons unknown.

Together, they form a foursome of failure akin to a parallel-universe "Wizard of Oz" collective, hitting the media trail to publicize their joint near-death experience and, in doing so, rediscovering their hunger for life. (Or money, whichever comes first.) None of this sounds especially amusing on paper, though I suppose it could be spun into the kind of chaotic media satire (more D.B.C. Pierre than Nick Hornby) where no one emerges clean.

That's not the target in "A Long Way Down," which does it damndest instead to haul this alienating scenario into the cheery self-help universe of Hornby's other, more successfully filmed work: whether you're a middle-aged lech, a struggling single mom or a manic-pixie-dream-girl with a missing sister, your problems aren't so dissimilar that you can't be rescued from the brink with a friendly heart-to-heart and a raucous middle-class vacation in Tenerife. That's a stunningly banal conclusion for a comedy that assigns itself such difficult material, and one that inadvertently diminishes any number of serious concerns -- cancer, disability, substance abuse, sexual abuse -- in its jaunty short-cut to hugging and learning.

Given such toxicity in its comic DNA -- I'll leave aside the Poots character's flippant digs at cerebral palsy, which aren't even daring enough to draw gasps -- "A Long Way Down" is at its best when it's merely inept. Scarcely one correct decision of direction, construction or characterization has been made across its 96-minute running time. For starters, cinematographer Ben Davis appears to have shot it with masking tape over the viewfinder; stray heads, elbows and shoulders interrupt frame after frame, mirroring the script's equally luckless pursuit of cluttered, freehand energy.

Chaumeuil is a proficient handler of frisky Gallic romcoms (notably the vastly popular "Heartbreaker"), but this material just isn't in his language, either verbally, tonally or socially: the film's depiction of the UK media scene, for example, could hardly be more clueless. If you can't get the real world right, it's harder still to invert it comically, and harder still when your most proudly repeated gag is piggy-backing on the five-year-old "Fucking Matt Damon" meme. All four (usually) likeable stars, sadly, go down with the ship, either checking out of proceedings entirely (Paul, in particular, appears to be nervously eyeing escape routes throughout) or mugging frantically on the spot. Neither approach is more effective than the other; in a film titled "A Long Way Down," there's only one way to the bottom.