Lego advent calendar
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'I dream in Lego': How to make a giant advent calendar from building blocks

22 December 2012 Last updated at 00:28 GMT

Duncan Titmarsh, a father of two and former builder, is the only person in the UK who can call himself a "Lego Certified Professional" - a title that he shares with just 12 other people around the world.

He heads a team of people that build structures and sculptures from the building blocks, and this year they have been tasked with creating a giant Lego advent calendar for London's Covent Garden market made from over 600,000 bricks.

BBC News went to meet him and followed the process from construction to installation.

Video journalist: Suraj Patel