HARRY Potter And The Philosopher's Stone is not a masterpiece. Adequate yes, good enough to satiate the Potter supporters' club young and old, but not a patch on the most magical films for children: Snow White And The Seven Dwarfs, The Wizard Of Oz, the Star Wars series, the Toy Story duo.

Why? The reason, as ever with book adaptations, is that the film must serve the book while seeking to attain an identity of its own. You hope it will gain as much as it will lose: for example, cinematic special effects, on the one hand; diminution of depth of character on the other. It doesn't.

The plot of J K Rowling's ubiquitous first Harry Potter novel has survived pretty much intact in its multi-million transformation to the screen, as the boy wizard's adventures at Hogwarts School of Witchcraft and Wizardry send him on his 11th birthday from orphaned loneliness in a suburban Surrey cupboard to an anachronistic boarding school education resonant of Enid Blyton's Famous Five or Tom Brown.

Bespectacled Harry (a shaggy-haired Daniel Radcliffe) is a chosen one, marked out to protect the Philosopher's Stone not only by the lightning scar on his forehead but, unbeknown to him, by his wizard family line. Being a chosen one, it is inevitable that neither Harry nor Radcliffe will be your favourite: Rupert Grint's Ron Weasley, the Artful Dodger to Harry's Oliver, and Emma Watson's savvy school swot Hermione Granger, Harry's pals in junior wizardry, are far more appealing.

The adults, meanwhile, are played in suitably fairy-tale manner: the once tempestuous Richard Harris is becalmed as benign headmaster Dumbledore; Maggie Smith reprises her prim Miss Jean Brodie, Scottish accent and all, as the assistant head; Robbie Coltrane is a big and cuddly Shrek of a Keeper of the Keys and Grounds, his Hagrid given a West Country burr as fulsome as his facial hair.

Alan Rickman's villainous Professor Snape slithers around like the Jungle Book snake crossed with Laurence Olivier's Richard III, and Ian Hart bizarrely impersonates Kenneth Williams as the duplicitous Professor Quirrell.

Director Chris (Home Alone) Columbus directs the school minutiae with all the rich detail of one of those Sunday teatime dramas on BBC1, be it the Great Hall meals, the school lessons or the scary corridors, but the Quidditch jousting game - the equivalent to the Pod-racing sequence in George Lucas's Star Wars: The Phantom Menace - loses its way in a heavy overcoat of detail and, as elsewhere, there is an absence of magic.

What Columbus lacks to go with the visual humour, the danger and the special-effect dazzle is verbal wit and darkness beneath the nice, middle-class surface, a failing so typical of an American director at the helm of a very British story. In particular, Harry's domestic misery is too quickly discarded.

So, Harry Potter's end of first-term report reads: room for improvement.