In "Bridget Jones: The Edge of Reason," the "singleton" Everygal neuroses of its titular British sweetheart have gone from endearing to downright insufferable.

Although still played warmly and winningly by the perfectly plus-sized Renee Zellweger, upon the advent of her still-fresh relationship with dashing, adoring, and a tad bit stiff barrister boyfriend Mark Darcy (Colin Firth), Bridget has become an embarrassing bundle of infuriating stock insecurities.

Jealous, suspicious, clingy, marriage-obsessed and irrational, in effect she's the antagonist in this romantic-comedy sequel. The hero is Mark -- whom she landed at the end of 2001's "Bridget Jones's Diary" -- for putting up with the torrent of rampant, relentless sitcom antics that stream unflatteringly and unchecked from the girl's vacillating self-confidence.

Firth has no choice but to play his role as a far-fetched, impossibly understanding fantasy lover who suffers endless embarrassment and annoyance but forgives Bridget's every stupid foible, even when she falls from rooftops while spying on him or accidentally bursts into rooms full of foreign dignitaries to make apprehensive declarations of love.

Far beyond disappointing in the wake of "Diary's" charm, "The Edge of Reason" is such a bitter-tasting fiasco from beginning to end that it can't even get by on the considerable wit of its talented returning cast, including Hugh Grant, again acing his role as Bridget's cheeky, rakish, Lothario ex-fling Daniel Cleaver.

Half the movie consists of jokes recycled from the first film: another chicken curry buffet, another ugly jumper on Mark, another nationwide broadcast of Bridget's butt during a TV-reporting gaffe, another silly fistfight between the men in her life, another scene in which she stands up for herself, cueing another Aretha Franklin song on the soundtrack, and another underdressed dash through bad weather to catch up with Mark and apologize for doing something foolish.

The remainder is made up of endless generic musical montages (no fewer than a dozen of them) and gimmick-driven, highly improbable episodic adventures. Clumsy Bridget goes skiing. Clumsy Bridget goes skydiving, somehow without an instructor and once again live on TV. Inexplicably, Bridget gets forced into a cheesecake co-hosting job on a suave (something she's definitely not) travelogue show, hosted by that cad Daniel Cleaver. This naturally leads to a romantic relapse, and quite unnaturally to an incident in a Bangkok women's prison that is played largely for laughs in appallingly poor taste.

The fact that Bridget herself is the worst thing about the movie -- despite Zellweger's best efforts -- speaks to the fact that director Beeban Kidron (best known for the awful "To Wong Fu, Thanks for Everything! Julie Newmar") had no respect for the source material (she barely uses author Helen Fielding's first-person diary voice-over) and had no ambition beyond making a kooky cookie-cutter chick flick. If you put this Bridget on a diet, all you'd have left is a routine Brittany Murphy or Kate Hudson movie.

The one thing this film seems to do well is to show the slow deterioration of Bridget's relationship with Mark, but it doesn't have the courage or originality to follow through. That would be far too unconventional.