For a lawyer who specialised in the arcane area of law known as “state immunity”, Hazel Fox was a remarkably influential figure. Her chosen subject is increasingly the cause of courtroom and political clashes. Fox, who has died aged 96, was one of the foremost authorities documenting the interaction between domestic and international legislation as aggrieved parties attempt to sue foreign governments for alleged torture, murder or financial misdeeds.
Her volume The Law of State Immunity, published in 2002 and already into its third edition (updated by her successor Prof Philippa Webb), analyses the cases through which the traditional, absolute freedoms enjoyed by states to engage in diplomatic relations have come under mounting pressure to give ground to other demands in an ever more interconnected world.
Fox appeared in few cases. One was a 1988 high court libel hearing in which Mohamed Al Fayed, the former owner of Harrods, sued a Gulf state ambassador for accusing him of impersonating an official in order to gain access to the VIP lounge at Heathrow Airport and attempt to import “prohibited goods”. The court dismissed the case on the grounds of inviolability of diplomatic documents.
Fox was also involved in a landmark torture claim brought against the Kuwaiti government in 1996 by Sulaiman Al-Adsani, a British national who had also been a member of the Kuwait air force. The judges in London dismissed the case due to state immunity.
In the case of Augusto Pinochet, the Chilean former dictator arrested in London in 1998 under an extradition warrant to face human rights abuse charges in Spain, Fox was reported to have been consulted by one of the UK judges. Her lucid, explanatory talks recorded for the United Nations Office of Legal Affairs on state immunity are still available online.
Fox was a legal blue blood: the stepdaughter of Lord Denning – the distinguished former master of the rolls – and wife of an appeal court judge. A sparky and dynamic presence, she moved in rarefied judicial and academic circles.
She was born in the colonial hill station of Maymyo, near Mandalay, in what was then British-administered Burma. Her father, Jack Stuart, was the engineer responsible for dams, water control and bridges on the Irrawaddy River; her mother, Joan (nee Elliot-Taylor), loved painting. Hazel was the second of their three children.
In the mid-1930s the family returned to England. Stuart advised on water irrigation in Palestine and Persia. Hazel was sent to board at Roedean, a girls’ school near Brighton. Along with the school she was evacuated to Keswick in the Lake District during the second world war. There she learned of her father’s sudden death in 1941, but continued lessons – not seeing her mother or siblings until weeks afterwards at the end of term.
At a school drinks party for parents, Joan Stuart met the also recently widowed high court judge, Tom Denning; the couple married in 1945. Hazel, who was head girl at Roedean, went to Somerville College, Oxford, the following year to study modern languages. She did not enjoy the course and, with the help of her stepfather, switched to jurisprudence, graduating with a first in 1949.
Moving to London, she joined chambers and in 1950 was called to the bar, where she practised for several years before marrying, in 1954, Michael Fox, a barrister who later became an appeal court judge.
She began to research, publishing International Arbitration: Law and Procedure in 1959 with the Foreign Office official John Simpson. Her language skills had tilted her interests towards international law and enabled her to read foreign court reports.
In the 1960s, Fox joined a group exploring legal records in the Foreign Office archives. Their investigations were published in the British Digest of International Law. While bringing up four children, she also served as a magistrate at Tower Hamlets juvenile court.
In 1976, she returned to Oxford to teach law, later becoming chair of the London Rent Assessment Panel and the London Leasehold Valuation Tribunal. In 1982, she was appointed director of the British Institute of International and Comparative Law (BIICL).
She revitalised the institute through fundraising and partnerships with industry and other organisations, turning it into one of the most influential UK forums for debate on international law. She also pioneered legal agreements that enabled prospecting companies to exploit oil and gas offshore in areas where maritime boundary disputes remained unresolved.
As general editor of the International and Comparative Law Quarterly, she was renowned as a tough editor, damning one book for being “a woolly diatribe”. Described by friends as “doughty” and a “formidable legal scholar”, she was the only member of a British legal delegation to post-Soviet eastern Europe to bring her bathing costume and insist on a dip in the Baltic.
Her laughter, charm and good humour inspired loyalty and affection. She named one of her cats BIICL (pronounced “Bikle”) as a play on her professional duties. At one point she was a candidate to become the UK’s judge at the European court of human rights in Strasbourg.
Fox returned to the bar in her 60s, appearing at the international court of justice in The Hague in a border dispute between Botswana and Namibia. She continued practising until her mid-80s.
In 1993, she was appointed an honorary QC for her legal scholarship, and in 2006 made a Companion of the Order of St Michael and St George (CMG) for contributions to international law and diplomacy.
Outside law, she loved gardening and reading. In later life she cared for her husband, whose final years were marred by blindness and Alzheimer’s disease.
She is survived by her children, Matthew, Patrick, Jane and Charles, and nine grandchildren.
• Hazel Mary Fox, barrister and legal author, born 22 October 1928; died 12 July 2025
