In this special programme, we bring together the ultimate rules of design – room by room. Across three series of The Great Interior Design Challenge our designers have come up with cost cutting, ingenious ideas about how to get a look for less, and they're all here. We also have some insider techniques for a better home used by our judges, Sophie Robinson and Daniel Hopwood, plus design secrets from the guest judges featured across the series – interior and architectural designer Oliver Heath, designer Orla Kiely and iconic interior designer Kelly Hoppen. We've broken the home down into five key rooms, and compiled our very own step by step guide on how to make the most of each one of them. Meanwhile, presenter and architectural historian Tom Dyckhoff gives his own historic tour of the house – explaining how our homes have shaped up over the years.