Lord Ralf Dahrendorf, the sociologist, politician and former longstanding director of the London School of Economics, has died.

He was born in Hamburg on 1 May 1929, the son of a Social Democrat politician who was arrested twice during the Nazi period. He was also briefly imprisoned by the Nazis himself.

Since his father's politics proved equally unpopular in postwar Berlin's Soviet zone of occupation, the family had to be flown to safety. Lord Dahrendorf later claimed he had been permanently marked by his early "experience in totalitarianism".

In 1952, after studying classics and philosophy at the University of Hamburg, he switched to sociology for a second doctorate at the LSE under Karl Popper, then spent the period 1957-69 as a professor of sociology in three German universities. A passionate liberal, he argued that democracy was a means for handling conflict, rather than for discovering some imaginary "will of the people" - a position he developed in detail in his celebrated books, Class and Class Conflict in Industrial Society (1959) and Society and Democracy in Germany (1967).

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As someone who once said he found "straddling worlds ... almost existentially necessary", Lord Dahrendorf moved into active politics for seven years as a German parliamentarian and then as a European Commissioner. His directorship of the LSE from 1974 to 1984 represented another major shift. Convinced that serious research could not be hurried, but would yield results "maybe tonight, maybe in 20 years' time, maybe never", he saw it as a major part of his role to "relieve academics of some of the burden of living in the real world".

After a less than happy return to German political and academic life, Lord Dahrendorf became warden of St Antony's College, Oxford from 1987 to 1997. He was knighted in 1982, and became a British citizen in 1988 and a life peer in 1993.

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Lord Desai, professor emeritus of economics at the LSE, recalls how, during a period of unrest, Lord Dahrendorf "was absolutely fantastic, let students occupy his office and just stepped over them to do his work. He didn't call the police or rant and rave.

"When the removal of the subsidy for foreign students cut decisively into his budget, he treated it as a challenge to be met, and managed to galvanise the entire school by promising no job losses. He was very bouncy, very engaged, a great conversationalist and bubbling over with ideas."

Lord Dahrendorf died of cancer on 17 June 2009 and is survived by his third wife, Christiane, and three daughters from a previous marriage.

matthew.reisz@tsleducation.com.