Phil Spencer visits one of the most celebrated stately homes in Britain - Castle Howard in Yorkshire; the setting for the TV adaptation of Brideshead Revisited, and a magnificent 'piece of theatre' in its own right. Nick Howard's family has lived there for more than 300 years. He leads Phil up the grand staircase, through the stunning crimson dining room and also opens up the family mausoleum. The great hall has Italian murals and a 21-metre-high dome modelled on St Paul's. In the original 18th-century ledgers, Phil uncovers the sheer scale of spending and reveals how it took years and an army of masons, craftsmen and artists to fashion this extraordinary building.