Hundreds of Hogwarts letters fly into the hallway as I walk up the path to Four Privet Drive just like they did in the opening chapters of Harry Potter and the Philosopher's Stone.

Envelopes flap in from every direction at this latest attraction at Warner Bros. Studio Tour in Leavesden, which replicates the iconic suburban setting that first drew us deep into the wizarding world of Harry Potter.

Last night I was lucky enough to look on as Fiona Shaw, who plays Aunt Petunia in the Harry Potter films, officially opened the door to the Dursley's domicile.

"It's great to be back home," she said, "It's been a long time since I saw it and it's marvellous that is is here. It hasn't been open to the public in all these years."

As reluctant as Aunt Petunia would have been to let strangers into her home, Fiona is hesitant. Hovering by the door after cutting the ribbon, she said laughing, "I have a very nice place under the stairs where I can put horrible children... and some of you older people too."

When we first meet Harry in the film and in the books, he is living in the cupboard under the stairs in the home of Uncle Vernon, Aunt Petunia and cousin Dudley. Their home is decorated in typical tacky fashion - ugly sofas, unattractive curtains, mismatching wallpapers and tiles - somewhat reminiscent of the Duckworth's living room in Coronation Street.

The Dursely's set has been launched especially as part of the tour's 15th anniversary celebrations of the first film, and for a limited time only, visitors will be able to step inside Four Privet Drive and peer into the living room, which has hundred's of Harry's Hogwart's letters suspended in the air as if they had just flown in through the fireplace.

In order to get the effect of letters ducking and diving about the house in the film, Warner Bros enlisted special effects supervisor John Richardson to a build a unique contraption.

He said: "We built a device to go on the back of the door that would allow those several thousand letters to come flooding into the room. For the film, we built it so that it could push around 200 letters through the letterbox at a time.

"On film we did around five to six takes of that iconic scene from two or three angles and there were thousands of letters."

As well as this letterbox device, which will be in operation during the tour, John added he was responsible for building the snake door in the Chamber of Secrets and the Gringotts vault doors.

The letters themselves were created by graphic designers Miraphora Mina and Eduardo Lima. The pair, who are known as MinaLima, designed many of the props in each of the eight films.

With the letters, Miraphora said they paid close attention to the little details, such as the emerald green ink, the lettering and font as well as the seal. "We created thousands of letters and then we got asked to make them a third of the size as they were too heavy for the owls to carry.

"The owls heads are tiny - we've seen it. When we were working on set, they had loads of animals - it was like a zoo. So often we would go over and you could see under all that fluff how small their heads were."

The duo also worked on the Black Family Tapestry and created it from scratch. The tapestry was featured for the first time in the Order of the Phoenix, but their most proudest designs for the films, Eduardo said was the Daily Prophet papers and the Marauder's Map.

"The props had a life of their own," he said, "we would design things and they would come back and ask us to change things - so we would see them evolve."

MinaLima weren't the only ones responsible for the props. Set decorator Rosie Goodwin, who worked on the last five of the Harry Potter films said they were often given a budget and a mission to find certain and quite specific props.

"A lot of the furniture and wallpaper used to decorate the Dursley's home was from a department store in Watford that has now closed (Watfordians will note Clements moved to smaller premises in 2000).

"I personally had to go find wallpaper for one of the rooms and a bin that Dudley would throw up in for the fifth film. I remember having to go on this hunt to try and find the right things and we often did go anywhere and everywhere.

"In the Deathly Hollows and for the Half-Blood Prince, we spent weeks working on the Room of Requirement, which had towers of furniture. That is probably one of my most memorable and we were going to auctions and as far as Norfolk to find the right stuff. It was the biggest set we worked and they were around 30 feet high."

Privet Drive opens its doors from Friday, May 27 to Monday, June 6. Details: