There's nothing swinging about the 1960s London where Demi Moore, as an ambitious diamond company exec named Laura Quinn, finds herself in the engaging, if flawed, "Flawless."

A heist picture, a feminist revenge fantasy and an excuse for Michael Caine to redeploy his Cockney accent as a wily old janitor, "Flawless" finds the actress in sharp, smart business attire, using a mid-Atlantic accent (she's a U.S. expat, educated at Oxford and long residing in England), and spending her off hours alone in her apartment, having a meal, a cigarette and listening to jazz.

The Beatles, "Darling," minidresses and mods — not part of Miss Quinn's equation. All she cares about is advancing her career at the London Diamond Corp. But after bumping her head on that glass ceiling — less-qualified, less-experienced male colleagues keep getting the managerial spot she deserves — it's time for some payback.

Actually, it's Hobbs, Caine's hunched-over custodian, who presents Quinn with the plan: He has figured out how to access the company's subterranean, steel-encased vaults — Hobbs is down there in the dead of night, mopping and sweeping — and how to steal enough shiny little multifaceted, multicarat gems to make them both millionaires.

Directed by Michael Radford ("White Mischief," "Il Postino") in a suitably classy, unflashy manner, "Flawless" offers the unexpected turns of a good thriller, but is compromised here and there by awkward, out-of-character moments (Moore's Quinn is cool and composed in one scene, inexplicably frazzled and panicky the next) and plot twists that are just a bit much. (The elegant businesswoman slogging through the London sewers with a faulty flashlight? Please.)

And the filmmakers' narrative device of framing Quinn's tale as a feature-length flashback doesn't pay off — we get a goody-two-shoes moral lesson at the end, and a look at movie studio aging makeup gone wild.

If the screenplay's tumultuous machinations — trouble in the South African diamond mines, sinister insurance company double-dealing — seem a bit strained, well, they are. But Moore gives an interesting performance, crafty, quiet and sexy in a buttoned-up way. Caine, pushing his cart around and not missing a trick, isn't exactly doing any heavy lifting, but his Hobbs is likable and full of surprises, too.