Potter about at Warner Bros Studios for a spell and discover the magic that made Harry happen We are standing in the Great Hall of Hogwarts where Harry, Ron and Hermione were first sorted into their houses. We have queued past the Cupboard Under the Stairs, and the secrets and sets from the eight Harry Potter films await. Already we are discovering that film-making involves a little magic of its own, as the ceiling of the Great Hall doesn't exist, at least not where one might expect. Instead lighting rigs peer down and the intricate ceiling shots one sees in the films are in fact images of an exact scale model which are added in at the post-production stage. Our youngest, aged eight, dressed up as Harry Potter, complete with scar, is intent on charging round as much as possible as quickly as possible. The three teenagers in our group, meanwhile - all devotees of the books and films - reverently look upon the relics from the screen outings of JK Rowling's wizarding world. It is worth noting that the Warner Bros Studio Tour London (actually just outside Watford), subtitled The Making of Harry Potter, is not a theme park. There are no rides as such, though one can climb aboard the Knight Bus, sit on Hagrid's motorbike and in Ron's Ford Anglia. It is more of a shrine to the HP movies and a love letter to the astounding technical and creative energy that underpinned the films. From set builders to costume, make-up, special effects and animatronics, the hidden arts of movie making are revealed and celebrated. The tricks of the eye employed by the cinematographers such as how Robbie Coltrane's Hagrid appeared to be a giant are as ingenious as they are interesting. Interiors of Snape's classroom, the Burrow, home of the Weasley family, complete with self-stirring pans, the glorious pomp of the Ministry of Magic and the staggering scale model of Hogwarts are spectacular and fascinating. There are many photo opportunities, from 4 Privet Drive to Diagon Alley which everyone loves walking up and down, so we have many digital mementos of our visit. Which is useful if you feel that you have already spent enough on getting in and don't want to unload any more in the outrageously expensive souvenir area. Could we find a notebook and pencil at pocket-money prices? There were, though, such delights as Hogwarts house scarves, £25, or chocolate frogs, £8, which we had to deny our lot, though we did buy a Quaffle between them. Tickets for the Warner Bros Studio Tour must be bought in advance. Prices for 2013 are £29 (16 and over) and £21.50 (5-15), www. wbstudiotour.co.uk/en/