What did you want to be when you grew up? A pilot? A train driver? Maybe an astronaut? Maybe you just wanted to play with Lego for your entire life, but surely that wasn't possible? Well, get ready to have your mind blown...

Not only is it possible, there's an actual job title: Lego master builder. As in The Lego Movie. And that's exactly what Duncan Titmarsh does for a living.

Yes, surrounded by Lego 24/7, Titmarsh has made a career out of playing with Lego - and he gets paid to do so. He is tasked with building a vast array of different displays, including miniature versions of skyscrapers, ocean liners and so much more it would be a very long list indeed. And recently, he donned his Christmas hat and built a 500,000 piece Father Christmas in his sleigh, complete with eight reindeer, to be the centrepiece of Lego's Christmas showcase in Covent Garden

His projects haven't always been that grand or complicated. Titmarsh started building Lego and earning money from it almost six years ago when he was approached to build a radio studio live on air for a local BBC radio station. That got him a couple of commissions and eventually enough work to consider doing it full time, leading to being offered the role of an official master builder with Lego in 2010.

Joined by fellow Lego builder Ed Diment, who Titmarsh met in a Lego builder's forum, he now runs the UK's only Lego building company, Bright Bricks.

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It employs over 30 staff that are full time Lego builders, so Pocket-lint dropped into the company's UK office near Farnham to see how you go about building such huge Lego models and what it is like to be effectively immortalised as The Lego Movie's Emmet.

It was disappointing that neither Titmarsh or Diment were wearing orange builders overalls when we saw them on a cold November morning, but at least we got them to agree that "everything is awesome" more so "when you work as a team".

And just like the movie suggests, working as a team is an important part of the build process here, especially when tackling builds with hundreds of thousands of bricks at a time.

The current project took over two months to build. Commissioned by Lego itself, this year's Christmas London Showcase features the whole cast: Rudolf and company with Santa Claus and his sleigh.

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It was a lengthy process that started with 3D rendered versions of the final build being on a computer. Those computerised drawings were then translated to on screen diagrams that look more like a elaborate game of Tetris than what any kid would be expecting to see in a Lego instruction manual.

"I stopped following instructions when I was about nine," explained Titmarsh.

Instead, he and his team came up with a plan and then loosely followed it, with higher ranked team members tackling the hard parts and newcomers left to do the monotonous brick stacking that made the epic sized creations.

This latest build involved working out everything separately first, from the legs and antlers of the reindeer, to the underlying steel work that has been used to make sure it's strong enough to withstand the elements. The team also had to manage the possibility of the characters warping during the build process. And they had to factor in how to make Rudolph's noise shine bright (it's a cavity with a light in it and some see-through red bricks, if you were wondering).

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While the likes of us mere Lego-building mortals believe that Lego's build quality is second to none, on big projects small discrepancies mean that over the course of the build, a reindeer's back for example, you might be half an brick out by the time you reach its tail. That as you can imagine, causes problems.

To combat this, Titmarsh, Diment and the team built the models with strut-like structures inside, rather than making them completely solid. The steel work strengthens everything further. And yes, they do also glue all the pieces together. But don't use "Krackle" as it's not good enough.

The Lego Santa and his sleigh was just this year's project, but chances are if you've seen significant Lego builds before in the UK they would have been built by Titmarsh and Diment's gang.

The two are responsible for the Lego Christmas tree that appeared in St Pancras Station in London in 2011, to various animals and creatures (including a sabre tooth tiger back for repair) at the Milestones museum in Basingstoke.

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Other former jobs included building a working model of a Rolls Royce air plane engine (the teams' most complicated to date), and a miniature version of The Leadenhall Building (Cheesegrater) in London, complete with 500 sets for the company to give away as gifts.

It's not all big builds that take months though. The company also does private commissions for Lego fans with a smaller budget. A favourite is a simple mosaic of a family picture will set you back around £100, while getting a life-size version of your kid will cost you around £6,000.

"Lego is actually really expensive to build with," explains Diment. "With most of the bigger projects you actually end up paying for the labour with the bricks themselves becoming insignificant to the price... it's not cheap."

It's not surprising. A big model equates to a lot of small bricks and someone has to piece them all together. There are no Mindstorm robots used here... yet.

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Thankfully, the builders do get to raid the cupboards of Bright Bricks.

The company has up to 12 million pieces of Lego in its warehouse, all segregated into tiny boxes and ready to be used. It's a neatness nerd's dream. There is even someone employed at the company just to re-sort bits that have fallen on the floor - you've got to start somewhere, after all.

With all this building knowledge and know-how why aren't Bright Bricks making their own sets?

"It's something we've thought about," explained Titmarsh, and he added that previous employees and friends have long been involved and successful with Lego Ideas. But there are restrictions involved in working with the Lego company.

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Bright Bricks gets to buy its Lego pieces directly from the toy manufacturer for a heavily discounted price - rather than buying them from the high street - but isn't allow to make its own sets. Even if done promotionally, it can only be limited to 500 sets with a bigger model the focus.

Talking to the two demonstrated that they both have as much excitement about building today as they did when they started, even though master builder Titmarsh told us he no longer gets the chance or urge to build at home.

After all, they are constantly surrounded by their former work. We saw dozens of models from past and present dotted around the warehouse, either in pieces or completed. There were awards they've built for events like the Golden Brickies and a huge replica of the RMS Queen Mary. There were real Lego sets scattered about too. And one of Titmarsh's favourite pieces, a Lego version of the London Tube Map, was hung proudly over the canteen area.

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With plenty more building still to be done we headed off knowing that, for most, the idea of becoming a master builder will now likely to be added to the job lists of kids. And judging by the fun the team at Bright Bricks have doing it, it sounds like a great career choice to us.