Born in Yorkshire on 19 October 1913, he was educated in the village school and then at Belle Vue Grammar School, Bradford. He read History at Downing College, Cambridge, resulting in an Upper First, then gained first class honours in both parts of the Law Tripos. A post-graduate LLB was followed by a scholarship at Harvard University, where he was awarded the Joseph Hodges Choate Memorial Fellowship. Back in London he taught for a while at the LSE. From 1939 on he was a Fellow of Jesus College, Cambridge. During World War II he served in the Intelligence Corps From 1955 to 1982 he was the Whewell Professor of International Law at Cambridge, and from 1982 to 1995 a judge in the International Court of Justice. He received honorary doctorates from several universities, including both Oxford and Cambridge, and won the Hudson Medal of the American Society of International Law. He was knighted in 1982. His publications included The Acquisition of Territory in International Law and he was an editor of The British Yearbook of International Law.