Inside every museum is a hidden world, and now, cameras have been allowed behind the scenes at the world-famous Victoria and Albert Museum in London.

Only a small part of the two million wonders in the collection are on display to the public. But in this series, we go behind closed doors to explore all the treasures of art, design and performance the museum has to offer.

We follow experts and conservators at work in this treasure trove of the nation's favourite objects, as they breathe new life into fragile marvels, uncover hidden stories and battle to keep the past alive.

In this instalment, we join Catherine Sargent as she prepares a new exhibition devoted to cars. She must ensure these large objects are displayed at their best, but as with all the vehicles arriving on loan from around the world, it's imperative that each one is moved into the museum without a scratch.

One of the largest and trickiest to transport is an extraordinary 1962 Chevy Impala, known as ‘Tipsy', arriving from Los Angeles. It's a unique car, that's been painstakingly customised to turn it into a ‘low-rider'.

With its low-slung chassis, gleaming paintwork and personalised motifs, the car was a six-year labour of love for owner Tomas Vasquez. Seeing Tipsy up close before it's moved into the museum, Catherine has some concern that it will be a tight squeeze getting it into the exhibition space. And with the added pressure of the owner flying into the UK to give his pride and joy one last loving polish before the opening, she has to ensure the move runs without a hitch.

Meanwhile, some of the finest of the V&A's one-off objects are in the Rosalinde and Arthur Gilbert collection, and curator Alice Minter is choosing a selection of her favourites to be displayed in an upcoming exhibition that will tour around the world.

She's found one rare masterpiece in storage that she thinks is going to be the star of the tour. It's a tabletop decorated using a technique known as ‘micromosaic', in which thousands of individually coloured pieces of glass are set into a pattern producing an effect like a painting. The process of making a micromosaic is so intricate that this tabletop would have taken a craftsman years to finish.

But Alice discovers that her beloved table is going to struggle to make the tour, as conservators have discovered cracks and swellings on the surface. X-rays reveal the full damage inside, with holes and corrosion making this object too vulnerable to move anywhere. Conservator Mariam makes the brave decision to conduct an experimental operation to save the tabletop from falling to pieces. She injects grout into the micromosaic, in the hope of gluing together its internal structure. Alice hopes this life-saving surgery will give this masterpiece a chance of going on display and being admired by the public.

Other rare survivors are unearthed in the Rock and Pop archive, as curator Vicky picks out the latest acquisitions for the V&A's collection of objects relating to The Beatles. She's interested in some of the animation cels from the groundbreaking movie Yellow Submarine. One of the film's animators, Malcolm Draper, has been invited in to explain how they were made. It's important for Vicky to understand the whole story of these objects to help keep alive the craft of drawing animation cels by hand.

Over in textiles conservation, a rare men's kimono is being repaired so it can be displayed in an upcoming exhibition. Worn by a samurai feudal lord in the late 18th century, Elizabeth-Anne Haldane has discovered rips in its fine inner silk lining near the waist that may have been made by a samurai sword. To have any chance of displaying the chequerboard-patterned kimono on a mannequin, she must delicately dye a patch and sew it into the torn areas.

In the jewellery galleries, conservators and curators are excited to take delivery of a rare buried treasure – a medieval jewel discovered in a field in Northamptonshire by a metal detectorist. The extraordinarily rare ‘cluster brooch' is made of gold and set with diamonds and a reddish stone called a spinel.

With only seven of its type ever found in the world, this is a special piece. Experienced conservator and gemologist Jo Whalley has the task of giving it a deep clean.

Using a mixture of spit and polish (as saliva contains enzymes that help to degrade soil and dirt), Jo must delicately remove the earth embedded in the jewel to reveal once more the full beauty of this miniature treasure.