Architectural historian. He is a Fellow of Kellogg College, University of Oxford and his main academic interests are in British and European architectural history, especially from the 18th–20th century, and the history of urban planning since the Renaissance. His books include John Nash: Architect of the Picturesque. He was co-editor of the revised volume on Berkshire in the Pevsner Buildings of England series, and of Sir George Gilbert Scott 1811–1878, and is now writing a history of the urban landscape in Britain from the Middle Ages to the present. He is also Editor of the Georgian Group Journal.