'What little girl does not dream of growing up a princess?" asks Emily Blunt in her voice-over at the start of the deliciously dressed-up protofeminist biopic The Young Victoria. But, you know, "even a palace can be a prison," she muses, ruefully.

Ah, yes. There she is, cloistered teen, granddaughter of George III, next in line for the throne, wandering the gilded halls and formal gardens, no friends, no fun, no iPhone.

What's a lonesome heiress presumptive to do?

Whether or not director Jean-Marc Vallée and writer Julian Fellowes' depiction of the accession of Britain's mighty 19th-century monarch is accurate, the film they've made, with its candlelight-flooded parlors, its royal balls and banquets, and its backroom scheming, stands as grand entertainment. It's a portrait of a young lady taking to power - tentatively at first, but soon with fierce conviction, with relish.

And Blunt, her eyes sparking, her manner playful, smart, and proud, shines in the title role. If the film itself isn't brilliant, its star most definitely is.

Much of the conflict in The Young Victoria comes by way of the Duchess of Kent (Miranda Richardson), Victoria's mother, who, closely allied with Sir John Conroy (Mark Strong, also the villain in Sherlock Holmes), is set to become regent if the king dies before Victoria turns 18. The duchess and Sir John have their own interests at heart and do their utmost to keep Victoria uncounseled, unprepared, helpless - wholly dependent on them. If only she would sign the regency papers allowing her mother to run the country.

King William IV, Victoria's uncle, cannot stand the duchess, and there's a terrific scene at his birthday feast in which William (Jim Broadbent, slurring marvelously) lashes out at Victoria's mum, drenching her in buckets of drunken invective while the assembled throng look on, scandalized, aghast (and enormously entertained).

And then Victoria is crowned, and talk of a husband begins in earnest. Of course, we know who wins out: Albert of Saxe-Coburg and Gotha, Victoria's German-speaking first cousin, played here as a soulful man of honor, and an eager lover, by Rupert Friend.

Albert's courtship of the queen is a complicated affair: He must gain her trust, thwart the ambitions of rivals, not seem too intrusive, and wait for her proposal. Complicating matters further: He seems truly to love her.

Vallée shoots in a smooth, dreamy style, pausing to linger on the exquisite costumes, the shiny new digs at Buckingham Palace. (Victoria was the first royal to live there.) A fine cast - Paul Bettany as Lord Melbourne, Thomas Kretschmann as King Leopold, Jeanette Hain as Victoria's confidante, Baroness Lehzen - keep Blunt on her toes.

She smiles, she purrs, she barks, she cries.

And the woman she plays reigned for 63 years.EndText