St Pancras: Who says Lego is just child's play? The model will spend the next month at Waterstones bookshop in Piccadilly, London, an appropriate venue as Elsmore has just written a book about how others can follow his lead and take the toy seriously. Called Brick City - Lego for Grown-ups, it is a beautiful manual, detailing how you, too, can piece together the Taj Mahal (28,000 pieces), St Basil's Cathedral (20,000) or the Empire State Building (13,000). What makes the book clever is that it contains lots of far less ambitious projects for children. A Hong Kong junk or a New York taxi or a London red telephone box would take a 10-year-old just an hour or so, rather than months. "It's not just for grown-ups, but anyone who feels grown up," says Elsmore. What makes his models particularly grown up is that people pay for them - an increasingly popular corporate ploy. Walk into the lobby of a large company and you as often bump into a sculpture made of Lego as a Damien Hirst. Last week, Elsmore was paid £1,500 for producing an 18in-long, Lego-made corporate logo. He is able to charge up to £25,000 to build a replica of a major building such as the Olympic Stadium or the Petronas Towers in Kuala Lumpur, which can take well over 300 hours. He is one of the very few to go from being an adult fan of Lego (there are about 3,000 members of Brickish, the UK adult Lego club) into a professional.Duncan Titmarsh, a former kitchen fitter, is another, and the only one in Britain to be officially recognised by Lego. He says: "Most days I do think this is a bit different, but you still have to go to meetings, you still have to meet deadlines and deal with clients. It can be hard work like any other job. Titmarsh was the man responsible for the 14ft, 400,000-piece Lego Christmas Tree in St Pancras station in 2011. Being a certified builder allows him to buy bricks directly from the Danish company at a discount. He has 3.5 million bricks in his workshop. As for Warren Elsmore, "I buy my Lego from the same outlets as you do. Occasionally I pop down to Argos. But like many fans he relies heavily on bricklink.com, a forum where people can buy and sell Lego parts, and even individual bricks. It currently has more than 200 million different pieces for sale. Titmarsh says the best thing about the job is the reaction of children. You give children inspiration. They see what you do, and they realise they don't have to do an ordinary job. Elsmore adds that Lego is the ultimate creative medium: "The only restriction is your imagination. You really can build anything you like. It's the sort of inspirational talk that astronauts of the 1960s used to fire up that generation. Children, get building.