Writer and architectural historian. He is joint editor of the Pevsner Architectural Guides, and author of several volumes in the revised Pevsner series, including those on the City of London, Westminster, Cambridgeshire, and Oxford and South East Oxfordshire (forthcoming, 2023). A Fellow of the Society of Antiquaries, he studied history at Oxford and completed a PhD on the Gothic Revival at the Courtauld Institute. He has held research positions at Oxford and at Cambridge, and teaches for the Cambridge History of Buildings MSt course. He has also published on British railways, including the major study The Railways: Nation, Network and People (2015).