Mike Nichols' new film is a boiling pot of lust, mistrust, and double-dealing, but its soap opera elements (and its soft-core porn elements) are elevated by the sophisticated gleam of its four well-heeled London desperadoes and the vicious dazzle of British playwright Patrick Marber's dialogue. Every time this bleakly funny wallow in contemporary bad behavior offers a guilty pleasure (a lewd, barking quarrel about fellatio, for instance), it counters with a blast of smarts. Just like Nichols' Carnal Knowledge, come to think of it. The beautifully portrayed combatants in the film's all-out sex war include Jude Law as a needy writer, Natalie Portman as a knowing waif just imported from New York, Croupier star Clive Owen as a Neanderthal dermatologist who makes your skin crawl, and a surprisingly effective Julia Roberts as a self-destructive portrait photographer. By the time they're all done switching beds, their relentless brawl has attained the kind of bruising authenticity most movies cannot dream of.