Man, British heritage cinema can be dull when assembly-lined for the export market. Laboring under lampshade millinery, hair that looks like cake, and more sumptuous banqueting than we should ever have to sit through, Emily Blunt is cute, sassy, and wildly improbable as the titular Majesty-in-waiting, who, in life, was a short, dumpy policy wonk and energetic social reformer. Biding her time to get out from under her vixen mother (Miranda Richardson, as always) and manipulative adviser, Lord Melbourne (Paul Bettany, a perpetually raised eyebrow), who wages war with other pols over her head, the willful young minx makes eyes across the water at hubby-to-be Albert (Rupert Friend, a total stiff well cast for once as the earnest Teuton who would sire nine children with Victoria). Sagging beneath reams of expository dialogue by Julian Fellowes, who also wrote the far naughtier Gosford Park, The Young Victoria reproduces the premise of The Queen (she outsmarts her worldlier advisers) with none of that movie’s cheek or verve. Plodding from one brocaded talkathon to the next, director Jean-Marc Vallée (C.R.A.Z.Y.) makes an unannounced left turn into action with a slow-mo assassination attempt that looks like a commercial for something, then proceeds, as planned, to the inevitable nuptial hour.