Keith Middlemas, who died suddenly at home on 10 July, was Professor of History in the School of Social Sciences from the University’s early days until his retirement as an Emeritus in 1998.

He was a prolific scholar whose many books cover an astonishingly diverse range of topics from shipbuilders on Clydeside to antique coloured glass on the Continent and life in a Northumberland village in the early 19th century.

Educated at Stowe and Cambridge, Keith came to Sussex in 1967 after military service in Kenya and nine formative years as a clerk in the House of Commons.

His early books made full use of his Westminster contacts and often reflected the preoccupations of the Conservative Party under Edward Heath. His three-volume edition of Thomas Jones’s Whitehall Diary 1926-30 (published in 1969) was followed in 1972 by a biography of Stanley Baldwin, three times Prime Minister in the troubled inter-war years.

On taking up his post at Sussex, Keith explored these themes further with Diplomacy of Illusion, a major study of Britain’s futile appeasement of Hitler’s Germany in the late 1930s, and his magisterial three-volume conspectus of British politics and society since 1940, Power, Competition and the State.

Determined not to be typecast as a historian of 20th-century British politics, however, Keith followed up this magnum opus in 1980 with a book on the dilemmas facing the Communist parties of western Europe and in 1995 a trenchant volume entitled Orchestrating Europe: The informal politics of the European Union 1943-95.

Urbane, aristocratic in bearing, a cultivated English gentleman from top to toe, Keith cut something of an unusual figure in the more radical milieu of the University in the 1970s and 1980s. Driving to campus in a series of brightly coloured Citroën 2CVs from his breathtakingly beautiful estate in West Sussex, he must have found the atmosphere in the Senior Common Room (in what was then the Refectory) not quite what he was accustomed to at The Flyfishers’ or The North London Rifle Club.

But he was a much loved colleague and teacher whose extraordinarily fruitful scholarly output, diplomatic skills and savoire faire were an invaluable asset to the University in its pioneering days.

Deeply involved in the establishment of the History subject group’s China exchange, he preserved it by securing financial help from his contacts in the City.

He wrote brief lives of the monarchs George IV, Edward VII and George VI, studies of the NEDC (the National Economic Development Council) and of the energy company Seeboard, and an intriguing book on art theft and art thieves.

Most exotic of all his publications was his work on the Cabora Bassa dam project on the Zambezi river in Mozambique, which appeared in 1975 under the title Engineering and Politics in Southern Africa.

After retirement Keith devoted himself to the history of his family and research into his Northumberland roots, with The Citizens of Alnwick 1831 and Kinship and Survival: The Middlemas name through 600 years.

Professor John Röhl