The son of an employee of the coal department at the Walsall Co-op and a school caretaker, Hinsley had come up to St John's College, Cambridge, as an Entrance Exhibitioner in 1937, and two years later was awarded a First in Part I of the Historical Tripos. Then, with Part II in view and no doubt another First on the cards, one day in the winter of 1939-40 he was asked to call on Martin Charlesworth, the Fellow of St John's to whom, together with F. E. Adcock at King's, the Cambridge end of the recruitment process for the Government Code and Cipher School had been entrusted. So Hinsley went to Bletchley, and for the time being History went to pot.
The experience of those heady days Hinsley later recorded in Codebreakers: the inside story of Bletchley Park, the volume he edited with Alan Stripp in 1993, whilst the achievements of "BP", since they were chronicled by him as editor-in-chief of the monumental British Intelligence in the Second World War (1979-90), and the contribution to the Allies' military operations provided by the breaking of the Enigma cipher, are now common knowledge.
Hinsley's particular activity at Bletchley was the study of German naval wireless traffic. This brought him into contact with Admiralty Intelligence, a liaison so intimate that a signal from Home Fleet querying some item "What is your source?" received the one-word reply "Hinsley". Years later Hinsley's "How I Sank the Bismarck" (which was the undergraduates' title for it, not his, or not entirely his) was a regular show-stopper at Cambridge college history societies.
In 1946 he married Hilary Brett-Smith, whom he had met at Bletchley and in whose serene company he returned to Cambridge to St John's where he had been elected to the Fellowship two years before.
The first time I met him, when I presented myself as a scholarship candidate in 1960, he seemed very old. I clearly remember wrongly spotting a resemblance to Franz Liszt in extremis. Indeed so old did he seem that on not seeing him about the place in 1961 I drew that wrong conclusion often drawn by those ignorant of the existence of academic leave. In fact, Harry Hinsley was very much alive in 1961, as in 1962 those of my contemporaries who were his pupils very soon discovered.
He was a wonderful teacher. Associating himself with an earlier age, he took the view that any intelligent historian could teach anyone, even a Johnian, any intelligible period of history. This conviction may have derived from his own experience at Bletchley. But what with Caius on the up, as it was then, in 1962 such studied amateurishness struck even us as high-wirism. Even so, with Hinsley it worked. "If you want to do modern this term, you'll go to Mr Miller, because he's a medievalist," he informed us. "But if you want to do medieval, then you'll come to me, because I'm a modernist." And we all assented to this and nodded gravely. And we weren't all fools, or just rugby players (which Hinsley himself had been, which was extraordinary, though, given that, the rest was altogether credible. He had especially enjoyed playing in the rain).
So I was supervised by him on "The Coronation of Charlemagne", which was only one of his set-pieces, and in accordance with some Hinslaic variation of the immutable Hinslaic precepts also went to him for modern things and benefited from his deconstruction of his own Power and the Pursuit of Peace (1963).
As a lecturer, he was spell-binding then, and 30 years on was spell-binding still. Less than a year ago I listened to him as he kept an enormous postprandial Cambridge audience on the edges of its collective seat while he reminisced on Bletchley days, without a note and for exactly the hour prescribed. Many of the audience on this occasion were candidates for the MPhil degree in International Relations, the degree course which Hinsley invented in the aftermath of Power and the Pursuit of Peace, and which has brought no end of interesting students to Cambridge in recent years, as well as spawning so many more more questionable courses in its wake.
Small of stature and dapper in appearance, Hinsley was notable for the distinctiveness of his pronunciation, the idiosyncrasy of which was more often feebly mimicked than artfully reproduced. "That was a caricature, wasn't it?" he asked after one more than usually accurate representation.
His contribution to St John's College, to which he was permanently attached for the last 52 years of his life, is incalculable. As Fellow, Tutor, President and Master, he was forever about the place. It was during his Mastership that at long last the college decided to "go mixed". Hinsley was not by nature a mixer, but once the change had been made he proved wholly supportive of it.
Because he was Reader in the History of International Relations, when in 1967 he said that there would be no war in the Middle East people took notice. And when, later that year, he said at lunch that Wilson wouldn't dare devalue and as he said it the Fellowship rose as one from its anxious eggs on toast and made its way down to Lloyds to see what could be salvaged, Hinsley's view was that the Fellowship was rushing it.
Shortly after being elected Master of St John's, in 1981 he was catapulted into the Vice-Chancellorship of the university. By 1981 Cambridge's spate of occupations and sit-ins was happily over. He wouldn't have been comfortable with those. The fashion now was for economy. Economy was a regime not altogether uncongenial to Hinsley. ("Just half a scuttle," he indicated from the chair at a meeting of his college council at about this time, as the fire was about to go out in the course of a discussion on the subject of how the college might cut corners.) In the history of the university he will be especially remembered for his promotion of the cause of early retirement.
Harry Hinsley was a man for all seasons, applauded and honoured both at home and abroad. Winter or summer, he would emerge in three-piece suit, plastic mac and invariable black beret. In mid-August, with the temperature in the nineties, the plastic mac and beret cut a particular swathe through the queues in the Cambridge Sainsburys. He was a rare man.
Francis Harry Hinsley, historian: born Walsall, Staffordshire 26 November 1918; War service, HM Foreign Office, 1939-46; Fellow, St John's College Cambridge 1944-79, 1989-98, Tutor 1956-63, President 1975-79, Master 1979- 89; OBE 1946; Lecturer in History, Cambridge University 1949-65, Reader in the History of International Relations 1965-69, Professor of the History of International Relations 1969-83, Vice- Chancellor 1981-83; Editor, Historical Journal 1960-71; FBA 1981; Kt 1985; married 1946 Hilary Brett-Smith (two sons, one daughter); died Cambridge 16 February 1998.