[1] He was called to the Bar by Gray's Inn in 1956,[1] while a junior legal adviser at the Foreign Office.
Over the period of some 45 years he served on many British negotiating teams abroad, dealing with a host of matters from Antarctic mineral resources[1] to human rights.
[2] He was a notable legal scholar and published a number of books including Oppenheim's International Law (volume one, 9th edition, with Sir Robert Jennings, 1992),[1] which remains the undisputed authority in the field.
1995 Sir Arthur joint the advisory board of the Liechtenstein Research Program on Self-Determination, Princeton University.
In 2000 he became a founding member of the Board of Advisors to the Liechtenstein Institute on Self-Determination at Princeton University, LISD, at the Woodrow Wilson School of Public and International Affairs.