Not many people develop a new art or science in their own lifetime - but Cecil Hewett has done it. He is the controversial teacher and prophet of a way of identifying and dating historic buildings. In Essex, Hewett finds the earliest-known half-timbered cottage in the country. In a Sussex church he identifies a wooden helm made in the days of the Anglo-Saxon kings. And at Salisbury he shows how the Christmas tree of woodwork inside the cathedral spire has kept it standing for over 600 years. Even ancient church doors take on a new aura when one of them is proved to have been covered with the skin of a human being. Hardly anyone believed that pre-Norman structural woodwork could have survived in this country. But Hewett now claims he has made the first discovery of a pre-Norman post that still holds up a standing building. Chronicle's specially commissioned radio-carbon dating reveals if he is right. Re-aired 28 May 1980