Haines was a Foundation Scholar of Bromsgrove School and educated at St. Chad's College, Durham, and Worcester College, Oxford. He holds research degrees of M.A. and M.Litt. from Durham and D.Phil. and D.Litt. from Oxford. He is a mediaeval ecclesiastical historian. Formerly Professor of History at Dalhousie University, Canada, and previously an assistant editor of the Victoria County History of Oxfordshire. He held a Canada Council Senior Research Scholarship 1978-1980 when he researched in the Vatican Archives. A Visiting Fellow of Clare Hall, Cambridge, 1987-8; he was made a life member of the college in 1990.
