Walking in the footsteps of Harry and Hermione

Fifteen-year-old fan Holly Hatfield guides us – and her dad – through the astonishing new Warner Bros Harry Potter tour near Watford

The idea of spending three hours walking through Hogwarts, discovering Diagon Alley and flying on broomsticks may leave some of you cold, but to any Harry Potter fan – and let's face it, there are millions of us – the Warner Bros Studio Tour London – The Making of Harry Potter – which opens to the public tomorrow, is an incredible, emotional experience; one I had to pinch myself to believe was possible.

First things first. This is not The Wizarding World of Harry Potter, Universal Studios' experience in Orlando, Florida. This isn't about rides. This is the real deal; the first time fans have had the opportunity to go behind the scenes and see the extraordinary skill, craftsmanship, imagination, dedication and attention to detail that made the eight Harry Potter films so special.

The tour lets visitors see and experience sets, props and costumes and even some special effects.

Without giving too much away, you enter into the Hogwarts Great Hall. Here, 400 students and teachers could sit at solid oak and pine house tables where "pupils" were encouraged to carve in their own graffiti (as production designer Stuart Craig explains: "This would happen in all schools!"). Daniel Radcliffe, Emma Watson and Rupert Grint literally grew up on these sets. You can see how they changed as the characters matured and the films became darker.

For example, the beds that were originally built for the boys' dormitory in Harry Potter and the Philosopher's Stone were much too small for the later movies and filmmakers had to find creative camera angles to fit the actors into them.

It's fun for all ages. As you enter, you are given a passport, for things to spot and get stamped. You can sit in the Ford Anglia in which Harry and Ron drive to Hogwarts in Harry Potter and the Chamber of Secrets and other film vehicles, or walk on Privet Drive!

Bring a camera, because photographs are encouraged and your BlackBerry will fill up in no time. The green-screen area is the exception.

Here you learn how the Quidditch games and the Weasleys' flying car were created. You can even experience how they were shot against green-screen before a backdrop such as London at night is inserted.

You might have to queue a long time here. But, which Potter fan wouldn't want to sit on a Nimbus 2000 broomstick, wearing a Hogwarts school robe (handily supplied for you)?

You can even purchase photos of yourself "flying", which are quite expensive at £12, but Potter fans will no doubt love them.

The level of detail is staggering throughout. In Dumbledore's office, every image of previous Hogwarts' headmasters was painted twice, once with eyes open and once closed to represent the illusion of night-time sleeping.

The sheer amount of craft on display that you never see or notice in the movies is mind-boggling. Everywhere it's evident the effort was made to create a set as realistic as possible; one that appeared lived-in.

The eager staff (some are former extras) are knowledgeable about everything Potter. It's a shame they're not costumed, but they're approachable and capable of dealing with real HP geeks. They'll need to be.

Visitors also get insight into pre-and post-production and the special effects of the films. In The Creature Shop you can see how hundreds of creatures and intricate prosthetics were made. Ever wondered how Dobby, the house elf was born? How werewolves change from man to wolf? Or even how Ralph Fiennes lost his nose to become He Who Must Not Be Named with those snake-like nostrils?

Is it worth the effort and money? I'd have to say yes, but I'm biased – see what my dad says (above). You can complete it in three hours, or linger longer. There's a Starbucks and a cafeteria. And you can even buy Butterbeer (it's yummy).

Actually, this tour would be an amazing experience for anyone, die-hard fan or not. For fans, it's like entering a world you have lived in for the past 10 years, discovering things about it you could never even imagine.

Everyone was walking around with a giant smile on their faces. This was our childhoods laid before us.

There's a wonderful surprise at either end. I won't ruin them, but you will never look at Hogwarts the same way again.

The ending actually brought tears of joy to many eyes.

Film buffs will be entranced by the craftsmanship, the detail, the secrets laid bare, and – who knows? - non fans may even be converted after a ride on a Nimbus 2000.

Who wouldn't want to do that?