He was
called to the Bar in 1935 and worked in Chancery Chambers until the outbreak of World War II. He spent most of the war as an
RAF Intelligence officer at GC&CS
Bletchley Park. He worked in '
Hut 3', where decrypted
Enigma messages were translated and analysed, and
Ultra intelligence was prepared for dispatch to commanders in the field. Calvocoressi rose to be head of the Air Section, which dealt with
Luftwaffe intelligence. In summer 1945, he was accredited by British Intelligence to obtain evidence for all four Chief Prosecutors at the
International Military Tribunal at Nuremberg. As a member of the British prosecution team, he cross-examined former German Field Marshal
Gerd von Rundstedt during the trial. Calvocoressi later advised the US Chief Prosecutor (General
Telford Taylor), who had been his Bletchley colleague, in some of the American follow-up trials (1946–1949). In 1945, he contested the general election, as the
Liberal candidate for
Nuneaton, finishing third. From 1950 to 1955, he worked at the Royal Institute for Foreign Affairs (
Chatham House), writing five volumes in the series of
Annual Surveys of International Affairs, which had previously been written by
Arnold Toynbee. From 1955 to 1966, he was a partner in the publishing firms of
Chatto and Windus and the
Hogarth Press. From 1966 to 1973, he was Reader in International Relations at the
University of Sussex, a post which was created for him. In 1973, he was enticed back to publishing by the offer of the newly created post of Editor-in-Chief of
Penguin Books. He was appointed Publisher and Chief Executive of Penguin in the following year. But he fell into disagreements with Penguin's parent company
Pearson Longman, and was removed in 1976. During this period (1955-1976), he was for ten years a part-time member of the
United Nations Sub-Commission on the Promotion and Protection of Human Rights, and was Chairman of the Africa Bureau, the
London Library, Chios Charities, and
Open University Enterprises Ltd. He also served on the governing bodies of Chatham House, the
Institute of Strategic Studies, and
Amnesty International. He wrote twenty books, mostly on contemporary history; one of these –
World Politics Since 1945 – passed through nine editions.
Threading My Way, an autobiography, appeared in 1994. He set private life before and above his career and never had cause to question this priority. In 1990, he was awarded an
honorary doctorate by the Open University. ==Personal life==