The opening hour of Harry Potter and the Philosopher's Stone, in which friendly giant Hagrid (Robbie Coltrane) plucks wizarding boy wonder Potter (Daniel Radcliffe) from suburban hell, is really all about what it means to have one hundred heads turn your way whenever you enter a room or, in scenes that play like premonitions of life in Rowling's flat today, have a gazillion letters demanding your presence flood your letterbox, or have people breaking down your doors to find out the real story behind the boy who brings magic to the lives of all those with whom he comes into contact. Once Potter enrols at Hogwarts Academy, the film is more interested in what it might be like to be a big fish in a small pond, as Harry, known to all his teachers as a major talent, is picked on by his rivals and finds it hard to live up to what's expected of him - because, as we all know, it's tough being a celebrity.
One of the joys of the film is this recreation of British private school education, for which we presumably have Rowling, and not American director Chris Columbus or screenwriter Steve Kloves, to thank. Next to everything within the Hogwarts universe - from Alan Rickman's science-lab tyrant and the ancient house system to what happens when someone falls off their broomstick or a troll (the film's equivalent of a cigarette fire) breaks out in the girls' bathroom - feels perfectly realised. The glaring exception is Quidditch, the high-speed ball game that takes place on and over a field round the back of the Academy, which is exactly the sort of arcane sport encouraged by those in private education, but demonstrates that Rowling, for all her grasp of character and story, has little real feeling for the rules of a game: why would a Quidditch player bother to throw balls through hoops, when they could win a match with a single catch?
With its cool effects for the kids and funny, eccentric character turns for accompanying adults, Rowling, Columbus and Kloves have stocked the film in depth, both a strength and a weakness. This world folds back in on itself, as Harry and best friend Ron Weasley (Rupert Grint) consume the sweets and trading cards that will no doubt make up the bulk of the Potter merchandise, coming soon to a store near you, but at least one of the executive producers looks to have held out for an emphasis on the expressiveness of human faces over CGI, on character development above marketing opportunities.
That said, this is a good blockbuster rather than a great one, stuck as it is with a wildly erratic selection of juvenile performances. Radcliffe underplays the role successfully, and while Grint is there mainly to provide salt-of-the-earth contrast to the lead's supernatural self-possession, too often he seems to be auditioning for the Jason Flemyng role in another Guy Ritchie about public-school geezers. Worse still is Emma Watson's Hermione, a character - and a performance - so shrill and arch as to be downright embarrassing at times. All of them have their moments, but the final forty minutes spent in their company, during which the plot signalled by the title eventually kicks in, do feel a little like being kept behind after class for a reason one can't quite fathom. Still, it'll be interesting when we get to the seventh Potter film, by which time Hermione will have become a preening sixth-form sexpot, Ron will be suffering from his first bad spell of acne, and Harry will be seeing who knows what "desperate desires" in the fabled Mirror of Erised.