Diplock, (William John) Kenneth, Baron Diplock 1907-1985, judge, was born 8 December 1907 at 8 Barclay Road, South Croydon, the only child of William John Hubert Diplock, solicitor, and his wife, Christine Joan Brooke. He was educated at Whitgift School and University College, Oxford, of which in 1958 he became an honorary fellow and to which he remained devoted throughout his life. He passed chemistry (part i) in 1928 and took a second class in chemistry in 1929. He was called to the bar by the Middle Temple in 1932 where he swiftly made his mark. But in 1939 he left his practice for war service, joining the Royal Air Force two years later and reaching the rank of squadron leader. He returned to the bar in 1945. He took silk in 1948 at the early age of forty-one, and acquired an extensive practice in substantial commercial work and as adviser to Commonwealth governments. When he appeared for the exiled kabaka of Buganda in 1955, the British government had to allow the chief to return home even though the case was lost on a technicality. He was recorder of Oxford from 1951 to 1956. In 1956 he began his judicial career when he was appointed a judge in the Queen's Bench division, with the customary knighthood. Promotion to the Court of Appeal and the Privy Council followed in 1961 and to the House of Lords in 1968.
To his generation Diplock was the quintessential man of the law, serving as a judge with great distinction and complete dedication for nearly half a century. During the two decades in which he served in the House of Lords as a judge, in the opinion of his brethren and the advocates who appeared before the judicial committee he was second only to the Scottish jurist Lord Reid [qv.] as the most distinguished judge of his day.
His was a supremely logical mind. With due respect for precedent, he would remorselessly pursue this path of logic confident that all legal issues were capable of solution. Many were the reversals in the House of Lords which he initiated on appeals from adventurous experiments by the Court of Appeal. Few thought that he was wrong, although some felt that he was so deft in demonstrating the misuse of logic in the Court of Appeal that he sometimes failed to appreciate that the lower court might have a point which required attention. But if there were, he would have said that that was a matter for Parliament and not for the judiciary. He was immensely industrious (he read Sir W. S. Holdsworth [qv.] for his light literary entertainment), and he was so well versed in the law that in discussion with his brethren some of them claimed that he had an almost hypnotic effect in swaying others to his point of view. At the same time, he always fiercely rejected any advantage gained by a legal trick. He had a clear idea of what the law should do to protect the citizen in dispute with modern authority and a clear concept of the consequences for municipal law arising from the new place of the United Kingdom within Europe. He believed that the progress towards a comprehensive system of administrative law, in which he played such an influential part, was the greatest achievement of the English courts in his judicial lifetime. From 1971 to 1982 he was chairman of the Permanent Security Commission and led inquiries into a number of security scandals, among them the Sir Roger Hollis [qv.] affair.
In October 1972 the government of Edward Heath, which was anxious over the intimidation of juries in the courts of Northern Ireland, appointed Diplock to chair a commission of three to consider legal proceedings to deal with terrorist activities in the province. By December of that year the Diplock commission was ready with its report which recommended that terrorist offences as defined in a schedule should henceforth be tried by judge alone. This was at once implemented and the courts became known as Diplock courts. The speed and certainty of the recommendations were principally due to the guidance and clarity of the commission's chairman. He gained honorary degrees from Alberta (1972), London (1979), and Oxford (1977).
While his career was the law and his home was in the Temple, Diplock's other enthusiasms were horses and the sport of fox-hunting which he pursued until late in life, indeed too late for the comfort of some lord chancellors. At the time of the Diplock commission he attended one meeting adorned with a resplendent black eye sustained by a fall from his horse. In 1974, when treasurer of the Middle Temple, on one Grand Day he headed his guest list with the Duke of Beaufort [qv.], master of the horse, and packed it with seven masters of hounds.
He married in 1938 Margaret Sarah, a nurse, the daughter of George Atcheson, who started and owned a shirt factory in Londonderry. The couple had no children. During their long life together they were rarely separated until 1984 when illness and particularly Sarah's loss of memory and ability to look after herself required her admission to hospital. There Diplock would visit her daily but she gradually became incapable of even remembering his visits. Her condition was a source of much grief to him in his last years at a time when he was presiding over the judicial committee of the House of Lords. In the end she survived him.
He died in King Edward VII's Hospital for Officers, London, 14 October 1985, only a few weeks after he had brought to a close his outstanding judicial career.