Professor Ralf Dahrendorf was prominent in public life in Britain as well as in his native Germany, not only as an outstanding authority in sociology and related disciplines but also as an influential man of action, in his roles as party spokesman and minister in Bonn, European Commissioner in Brussels, head of two famous educational institutions in Britain, and active member of the House of Lords.

Ralf Dahrendorf was born in Hamburg in 1929, the son of the Social Democrat politician Gustav Dahrendorf, an anglophile, and Ralf and his younger brother, Frank, were both given English names.

The circumstances of Dahrendorf's boyhood in wartime Berlin were turbulent and even tragic. In July 1943 all four of his grandparents perished in the massive British air raids on Hamburg. A year later his father, who had been involved with other leading Social Democrats in the background of the plot to assassinate Hitler, was sentenced to prison, and was released only when the war ended. Meanwhile, the young Ralf Dahrendorf, who was a member of a discussion and reading group organised by an anti-Nazi teacher, was arrested and imprisoned in a concentration camp to the east of Berlin. Here he witnessed among other things the exceptionally brutal execution of a Russian prisoner of war for stealing some margarine.

Dahrendorf was freed in the general confusion accompanying the Russian advance on Berlin. Here, as the life of the city was being re-organised, the Russian authorities made him responsible (although he was only 16) for transport and food distribution in one of the urban districts. His father accepted a position in charge of power supply in the Soviet Zone but fell out with the Russians and succeeded, with British help, in getting his family to Hamburg. This came just in time to save them from persecution by the authorities, as Gustav Dahrendorf was one of the Social Democratic leaders who resisted the forcible merger of their party with the Communists, to form the “Socialist Unity Party” of the Soviet Zone. In Hamburg, in the British Zone, Ralf Dahrendorf came to know some of the leading officials of the Control Commission, including Robert Birley, Professor T. H. Marshall and Noel (later Lord) Annan. This began a connection with Britain which was to last the whole of his life: he was deeply impressed by a visit to the Anglo-German discussion centre at Wilton Park early in 1948, and when he entered the House of Lords in 1993, Noel Annan was one of his sponsors.

Times Archive, 1974: Wunderkind with a vision of Europe

His political opponents sneer at him as an academic manque while his academic detractors put him down as an intellectual poseur

In 1947 Dahrendorf began his studies of philosophy and classics at Hamburg University. His doctoral dissertation, completed when he was 22, was concerned with the concept of justice in the thought of Karl Marx, and was soon published as his first book, Marx in Perspective. In the same year, 1952, he came to the sociology department of the London School of Economics, where T. H. Marshall was now a professor, and where his London PhD, on the nature of the unskilled labour force, marked his transition from philosophy to sociology. His fellow-graduate students at “the School”, who included A. H. (“Chelly”) Halsey, David Lockwood, Ronald Dore, Jean Floud and Asher Tropp, were attracted to American sociology because it then firmly believed in itself and in its capacity to become a science. However, they continued at the same time to see some value in Marxism, even in those days of the alleged “end of ideology”. The intersection of these two preoccupations resulted in their characteristic quasi-Marxist revisionism within the transatlantic corpus of sociological theory of the time: the “functionalism” of Talcott Parsons, they argued, overrated harmony and value consensus in society, and underrated the importance of power-relationships and of conflict. A criticism of this view is the main concern of Dahrendorf’s Class and Class Conflict (German edition 1957, English translation 1959), one of the books which established his reputation as a sociologist.

It may be said that he owed his rapid rise to academic prominence partly to the fact that, when German intellectual life was being revived in the post-Hitler years, in a world dominated by America, in sociology as in other areas, he was one of the first of the rising German generation to acquire confident familiarity with the new centres of activity, such as the Centre for Advanced Study in Palo Alto, California, where he spent the academic year 1957-58.

His career progressed rapidly. Junior appointments in Frankfurt and Saarbrücken were followed by professorial posts in Hamburg, Tübingen and Konstanz. At Konstanz (a newly founded university, called by some “the Sussex of Germany”), he was the first dean of the social science faculty.

Two other themes became prominent in his life and work. One was the influence of the political liberalism of Karl Popper and of the economic liberalism of Milton Friedman, which he was later to record in his BBC Reith Lectures of 1974, The New Liberty.

This commitment to liberalism manifested itself when he entered German politics in the 1960s not as a Social Democrat like his father, but as a liberal, a member of the Free Democratic Party. In his writings, too, he saw the need to go beyond the “social-democratic consensus”, and to face the problems engendered by the very success of that honourable tradition. His view, significantly, was that in the modern world liberty was more at risk than equality.

The other prominent theme in Dahrendorf’s life at this stage was the personally felt problem of the proper relationship or balance between fact and value, scholarship and politics, thought and action.

It was in a way ironical — since his political views moved mildly to the right — that his life continued to be based firmly on the essentially progressive concept of the unity of theory and practice, and a determination that the world be not only understood, but also changed.

The outward manifestation of this resolve was a rapid progression in public life, from an advisory post on education policy with the Baden-Württemberg Land government to membership of the Land parliament (1968-69) and of the national executive committee of the Free Democratic Party (1968-74).