From the outside, it’s an ordinary looking unit on an industrial estate.

No-one would ever know what marvels lie within.

But open the door and you’re admitted to an Aladdin’s Cave of hundreds of the most astonishing dresses, jackets, shoes and hats, which make up the wonderful wardrobe of Wicked.

Here, in a nondescript building in Stratford-upon-Avon, is where all the costumes ever worn by the cast members in European productions of Wicked since 2006 are stored.

And this is where fabrics, beads, ribbons and zips are amassed, waiting to be sent to London to be made into glittering outfits for new productions, such as the current UK tour which has just arrived at the Birmingham Hippodrome.

Its doors have never been thrown open to the media before, until now.

The location is the choice of costume supervisor Margie Bailey, who has looked after Wicked since it moved to the West End from Broadway eight years ago.

She moved to Stratford with her husband who works for the Royal Shakespeare Company.

“It makes sense to have a central location,” she explains.

“We can easily get a spare costume or piece or fabric down to London in an emergency. It takes as long to get from Stratford to London as it does to get from one side of London to another.”

Come away from Wicked, a spellbinding show which is playing Birmingham for nine weeks, and you’ll remember the songs, the wit, the love affair – and definitely the costumes.

Sumptuous, fantastically coloured and lovingly hand made, they are simply stunning. Close up, the attention to detail is extraordinary.

It’s no surprise that the costume designer, Susan Hilferty, has won half a dozen major awards, including a Tony, for her work.

While almost all the costumes and fabric are neatly packed away in Stratford, two dresses are proudly out on mannequins – Glinda’s Bubble dress, which Margie refers to simply as Bubble as if talking about a friend, and Elphaba’s intricate Wicked Witch dress.

Unless you were on the front row, it’s doubtful you would see the extraordinarily intricate work that goes into the dress.

But close up, you see the beaded and embroidered bodice is made up of 29 different fabrics, including strips of velvet in rich colours.

And you notice that the skirt has almost 50 layers of gathered ruffles.

No wonder the fabric costs £5,000 per square metre and the dress takes three weeks to make.

The dress in Stratford is actually the one worn by Wicked’s biggest star, Idina Menzel.

So why go to all this trouble and expense when most of the audience can’t see it?

“Because if we didn’t, they wouldn’t look so beautiful,” explains Margie.

“It all adds up to the overall effect. We don’t want people to feel short-changed, to go away thinking the costumes were just average. We want them to be dazzled.”

Then there’s Bubble, which contains almost 100,000 sequins of 20 different types.

Glinda sheds some at every performance, so a man is employed to go into the theatre four days a week just to sew them on again.

Bubble requires the most upkeep, but one of the most expensive dresses, at £25,000, is a rich claret one belonging to head teacher Madame Morrible.

The beadwork is exquisite – but then, the person who sews all the beads on also does so for the Queen’s dresses.

Venture further into the Stratford-upon-Avon base and you discover it’s like a sophisticated Ikea. A database holds information for every item of costume, every pair of shoes and every bolt of fabric, with details of where they can be found. And each has a tag attached with a reference number.

It means Margie and her assistant Hannah Williams can easily lay their hands on what they need.

The costumes are hung on rail after rail, in plastic bags to protect them, closely packed in tunnels of treasure.

They are normally kept in the dark so they won’t fade, and at a low temperature.

When a new production like the current UK tour starts, that means making hundreds of new costumes.

That happens in London but everything is brought together first in Stratford.

 

“To pull together all the costumes for a show like Wicked takes 4,000 fabrics and three weeks, so we need somewhere to store everything,” explains Margie.

“We do reuse and refurbish as much as possible. For the tour we’ve had to change 550 items and for the West End we produced 1,200. That’s a lot of name tapes to sew in.”

Fabrics are supplied from all over the world while several are bespoke, made just for Wicked.

“We can’t just go to the shops and find fabrics,” says Margie.

“We keep samples of all the fabrics used since 2006, which we use as a guide if we need to replace them.

“We never move away from the set colour palette. Everything is exactly as it was in the original show and if you go to see a production of Wicked anywhere in the world, the costumes will be the same.

“They are all of a very high standard. The costume makers give it their very, very best. They are supreme, the best in the world and deserve a medal.

“One woman has made 25 Bubbles and never drops her standard.”

One of the most striking scenes is when Glinda and Elphaba arrive in the glamorous Emerald City, marked by the ensemble cast wearing beautiful costumes in every shade of green.

To make them, white ribbons are bought and then dyed exactly the right colour. One sumptuous jacket is made just of bespoke ties.

Then there are the monkey suits, individually hand-painted to accentuate the muscles on each actor’s body.

The trims are packed in boxes with intriguing names like ‘Artistic ribbon’ (from New York, apparently) ‘fantastic ribbons’ and ‘Australian leathers’, left over from making hats on the Down Under tour.

In the corner is a washing machine. Surely most of the fabrics are too delicate for that?

“We can wash Bubble,” says Margie, of the five Bubble dresses stored in Stratford.

“We take off the petal layers with the sequins and give her a gentle machine wash.”

All these costumes need a lot of attention, so as well as the touring crew, 12 extra local dressers will be recruited for the Birmingham run.

Margie will take the opportunity to set up a studio in Birmingham to take the costumes through their annual maintenance overhaul.

She’ll be seeing the show, of course. She sits in the audience of Wicked about every three months, taking her binoculars so she can check the costumes are up to scratch.

“I fall in love with the costumes,” admits Margie.

“I think a job only becomes a challenge when you fall out of love, but I don’t think I ever will with these costumes.

“I look forward to coming into work every day, it’s endlessly fascinating.”

* Wicked plays Birmingham Hippodrome until September 6. For tickets, ring 0844 338 5000 or go to www.birminghamhippodrome.com .

Wicked Facts

* Wicked premiered on Broadway in October 2003.

* It has been seen by 42 million people in 13 countries and there are up to nine productions running at any one time around the world.

* With clever songs such as Defying Gravity and Popular, Wicked has won 100 awards.

* It is based on Gregor Maguire’s novel Wicked, published in 1995, and tells the story of what happens before and after Dorothy arrives in Oz.

* It features two unlikely friends, Elphaba and Glinda, who meet as sorcery students.

* Green-skinned Elphaba somehow gets labelled as the Wicked Witch of the West, but is she really the villain of the piece?

* The cast is led by Nikki Davis-Jones and Emily Tierney as Elphaba and Glinda, plus Coventry’s Liam Doyle as their love interest Fiyero.

* The touring version of Wicked moves about the country in 12 huge trucks, with three just for the costumes.

* There are 81 crew members on tour, plus 40 freelancers used to move the show in and out, plus the 38 cast members and 12 in the orchestra.

* There’s a moving dragon who watches over the show.