It’s fitting in The Duchess that, despite the obvious passage of years, no one seems to age.

It’s a wonderful analogy for British film and the way it seems frozen in time. No film industry in the world more needs a swift kick in the knickers. If Martians landed and could only use modern films to assess British culture, they might conclude all Britons present are gangsters and all Britons past were bed-hopping aristocrats.

The Duchess, as the title implies, falls squarely in the aristocratic bed-hopping category, the latest “sumptuous” fall film built on grand marble estates, beautifully elaborate (and unbelievably spotless) period costumes, and Keira Knightley’s pout.

Saying that about Knightley is easy and unfair. She’s a capable actress, even if she doesn’t always choose to show it. Few 22-year-old performers could reasonably be trusted to carry a film of this scope. While not equal to her magnetic turn in 2005’s Pride and Prejudice, her performance proves dutifully tragic as Georgiana Spencer, an 18th Century aristocratic wife trapped by matrimony and tradition.

Married as a teen, Georgiana becomes the wife and virtual slave to the quietly caustic Duke of Devonshire (Ralph Fiennes), who needs a male heir and sees little point in marriage other than productivity. Taken to the lovely but dead surroundings of his London estate, Georgiana’s womb proves to be an X-chromosome factory, sprouting one daughter after another to the Duke’s silently burning disapproval.

Disappointed by his wife, the Duke takes up with other women. He eventually seduces his wife’s best friend, forcing the three of them to live in the same home. In response, Georgiana explores a romance with Charles Gray, an adolescent flame and a rising politician. Her only other comfort is her growing public adoration, as her fashion and frivolity makes her a star of the 18th Century press. As a playwright puts it, the Duke is the only man in London who isn’t in love with his wife.

What has the modern British press all atwitter is that, in real life, Georgiana Spencer came from the same family as Lady Diana Spencer. Given the seeming similarities of their fates, there appear to be “overtones” here.(Or are they “undertones?”) Like Stephen Frears’ The Queen, The Duchess is a fragment of continuing British Diana obsession that, as an American, seems alien. It comes from something in the British soul that I don’t quite understand. Without it,

I’m not sure the film packs the same energy.

Costume dramas are notorious for swallowing their characters in beautiful fabric .To the credit of the actors, The Duchess avoids this fate. That said, what does get swallowed is the story. Director Saul Dibb doesn’t add much to a familiar feminist nightmare of aristocratic patriarchy. It would help if the men weren’t so weakly drawn. It’s hard to share in an obsessive love for a man living up to a last name of Gray.

My own sense is that if you want a really good film about the injustices of European aristocratic life, you should hire an American director. Perhaps it’s because Americans are less dazzled by the surfaces and more awake to the dark humor of it. Sophia Coppola’s Marie Antoinette captures the dehumanizing lunacy of court life at Versailles. Stanley Kubrick’s Barry Lyndon turns the aristocratic costume drama into a biting dark comedy of the human condition.

Like most European period pieces, The Duchess pays unbending attention to the details of court life. These films make you wonder if British film producers keep a storage shack of candelabras, and whether British drama training requires a course in dorky court dances.

But the question remains, how often can the British get past the pomp and the sex and the reverence for their history to deliver a period piece that is something truly more than itself? One time too few, for certain.