How one wants to like Driving Lessons, a film which supports the idea of children pursuing their true path in life, whatever objections family and environment may raise. The notion of a wacky, flamboyant dame, as in Dame Evie Walton (Julie Walters) here, a drunken actress who takes in an impressionable youth, as in Ben (Rupert Grint) here, a shy poet-in-the-making son of a preacher, is at least as old as Auntie Mame. Okay, if not the most earth-shaking stuff so far, but writer-director Jeremy Brock is fuzzy in his delineation of Evie, who is more monstrous and infuriating than anything else-you wonder really what Ben sees in the daft old bat-and the denouement is lamentably over-the-top.

Brock has also laden poor Ben down with the kind of family situation that, in this millennium, could only be described as Dickensian, with a fanatically controlling mother (Laura Linney, not at her best, but actresses rarely are playing cartoonish gorgons like this) and an ineffectual sop of a dad (Nicholas Farrell), more interested in birdcalls than his son. (You might notice that easy clichés run rife here.) Naturally, Mama disapproves of Ben's new friendship and does her utmost to keep them apart, but, in one of those woeful, free-for-all public spectacles British cinema is so full of, personal independence and empowerment win the day. Evie barges into a religious pageant in which Ben is trapped, playing a holy eucalyptus tree, and one's impulse is to groan, rather than cheer.

Walters, as is her wont, munches scenery like a beaver in a woodpile. She's initially rather funny with her unhinged mind-works and brazen utterances, but too many alcoholic outbursts and pitiful breakdowns wear down your patience. Large parts of the film are somewhat saved by Grint (of the Harry Potter films), who appears by turns geeky and then eerily beautiful, and has an authentic sweetness amid all the trials he's put through. At one point, he performs Shakespearean scenes with Walters, and his reading of lines as Oberon and Othello-so preferable to those of the screenplay-have a real distinction.