Mind the gap … between all 637,903 Lego bricks used to make this life-size Tube carriage. It is on display at the world’s largest Lego store, which opened today in Leicester Square.

The London flagship has been two years in development and also features models of a dragon, the Elizabeth Tower and Big Ben and a Royal Mail postbox. The creations on display are made from 1.7 million bricks and together weigh five tonnes.

More than a third of those bricks went into the London Underground carriage, created in partnership with Transport for London . It took 4,000 hours to make and features an unusual passenger — a model of Shakespeare.

Dylan Collie, 12, was given a sneak preview of the store and said: “There is so much to do. It was bigger than I expected and sitting on the Tube carriage makes it feel like the whole world has turned into Lego.”

The 914 sq m store also has a 1:15 scale model of the Elizabeth Tower and Big Ben, which is 6.5m tall and weighs 1,035 kilograms. It took six model builders nearly 3,000 hours to create from 344,030 bricks, features a working clock and chimes with the sound of Big Ben . There are also models of a telephone box, the Leicester Square Tube roundel and an Underground map.

Attractions include the world’s first Lego Mosaic Maker, which allows shoppers to buy a personalised Lego mosaic portrait. The machine captures the portrait before producing instructions and the bricks required to complete the image. There are also play tables where children can sit and build.

John Goodwin, executive vice president and chief financial officer of the Lego Group, said: “We want to inspire and develop children through creative play experiences — and this store is all about that.”

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LEGO fan Dylan Collie got an early look inside the new store...

I love LEGO. I love deciding which sets I am interested in, I like reading and researching it, building it, playing with it and then making something else from it. I play with it for hours.

With the world's biggest LEGO store opening its doors in Leicester Square I took my love of LEGO one step further and actually became a LEGO masterpiece

Among the 1.7 million bricks used to build the vast models in the store there is a booth that turns people into 4,502 pieces of LEGO.

The Mosaic Maker is a world exclusive to the London store which scans the face like in a passport photo booth, and then converts the image into a LEGO pixels.

I am now officially a LEGO set.

For me it was the highlight of my visit to the store, which began by walking through the Victorian tube station 'iron gate' made out of tens of thousands of black bricks.

After just a few minutes taking it all in I realised the shop had been made just for me... and the millions of other LEGO enthusiasts.

The flagship store is made up of two floors with jaw-dropping replica models which took 10,000 hours to create.

The centrepiece is a beautifully intricate, two-storey chiming Big Ben with a working clock face. The hourly chimes were the only clue to how long I had been in there.

Brickley the dragon, complete with iconic London accessories of a bowler hat and black umbrella, is also coiled ready to welcome visitors.

As I sat in between life-size models of William Shakespeare and a Queen's Guard, and just a few inches away from Her Majesty the Queen, I thought there couldn't be anything more English.

The walls of the store are lined with sets to buy, from Architecture, Star Wars , Ninjago, Nexo Knights, Friends, LEGO City and to the cars and buildings of the Creator series.

It is an experience where you can play at the activity station, although you might be rudely interrupted by an insistent remote control R2-D2.

There is also the pick-a-brick wall- the master build station where you can add your own flair to London landscapes but get help to build an original design.

It is the subtle yet stunning details that make LEGO so appealing to all ages and all levels of ability, from the stunning 3D landscape that cascades on the stairwell , to the "Mind the Gap" tube station platform for people waiting to get in the lift, complete with dirt, litter and a tiny spider.

The store will be a must-see for Lego enthusiasts of every age, as well as tourists from all around the world descending on the capital.

Find the store at 3 Swiss Court, W1D

Follow Lizzie Edmonds on Twitter @LizzieEdmo