He was a fine advocate, a brilliant scholar, a loving family man and a leading architect of the nascent system of international criminal trials. His special contribution to human rights was marked in the Hague courtroom where he had been appearing, shortly after it heard the news of his death. The judges and lawyers all stood in his honour, with the words ‘Today, we are all wearing John Jones’ robe.’

John was called to the English Bar in 1993 after a PPE degree from Oxford and a law course at City University. He then took a Masters degree at George Washington University. It was at the Hague that his special ability was first recognised – by none other than Professor Antonio Cassesse, a founding father of international criminal law, who had become President of the War Crimes Court for the Former Yugoslavia (the ICTY). He engaged John to help draft its rules of evidence and procedure, and then dispatched him to Arusha to do likewise for the court set up to punish the perpetrators of the Rwandan genocide.

It was at the UN’s Special Court for Sierra Leone that John made his first permanent mark. I had been concerned, as its first President, that international justice had, ever since (and including) Nuremberg, been delivered by courts which had an in-built bias towards the prosecutor: equality of arms required a defender. John was appointed to head the new Defence Office, and his dedicated work not only proved that such an office was necessary in the interests of fairness, but ensured that it would be replicated in other courts – including the new International Criminal Court (ICC). Last year, he represented one Sierra Leone convict – Charles Taylor – now serving a 50-year sentence in a British prison, in an attempt to have him transferred to a prison in Africa.

John’s academic excellence enabled him to preach what he practised: he wrote a textbook with Cassesse on the Rome Statute (which set up the ICC) and another with his friend and colleague Steven Powles on international criminal practice. Last year, with his wife, the Slovenian lawyer Miša Zgonec-Rožej, he wrote an important article on the rights of suspects for Amal Clooney’s book on the Lebanon Tribunal.

In 2005 he joined Doughty Street Chambers, where he specialised in extradition law and became a part-time immigration judge. He appeared for governments as well as for potential extraditees, and earned praise from judges for the fairness of his approach. Throughout his legal life his scholarship enabled him to intellectualise what he was doing daily in the forensic arena: he produced the valuable Extradition and Mutual Legal Assistance Handbook. He appeared in a number of leading extradition cases, including a Supreme Court decision about the needs of vulnerable children caught up in the process. He was a member of the team acting for Julian Assange and it was his submissions that persuaded the UN Working Group on Arbitrary Detention this year to rule (much to the annoyance of the UK Government and newspaper editorials) that Assange was being wrongfully detained.

John was appointed QC in 2013, and worked full time at the Hague the following year as Resident Director of Doughty Street International. He represented some of the most demonised (and, it must be said, a few of the most demonic) defendants, always putting up the legal arguments they were entitled to make and thus ensuring that justice upon them would be seen to be done. He appeared for Saif Gadaffi and the Libyan spymaster and mass-murderer al-Senussi, in appeals to have them tried for crimes against humanity by the ICC, which cannot pass a death sentence, rather than lynch-law Libyan Tribunals.

It was at Oxford that John’s extraordinary abilities were first noticed by his chums: a photographic memory for every Blackadder and Monty Python script ever written, which he would perform for their delight. Later, on his legal travels, he had the capacity to learn the language of all the countries where he was stationed – Bosnian, Swahili, Sierra Leone Pidgin and even a strange tongue – a clicking language in central Africa which he said helped him to communicate with Orang-utans. He became a trustee of the Orang-utan Protection Foundation. The other species he strove to protect was whales, for whom he acted in cases brought against Japan.

John usually acted in death penalty and other deserving cases free of charge. He gave of his time unstintingly to mentor young lawyers and to assist colleagues with creative arguments in his specialities. His advocacy was fluent and unflappable, his scholarship unimpeachable and his sense of humour always intact. He leaves proud parents, Peggy and Hugh, his loving wife Miša and his two young children. ●

Doughty Street Chambers has set up the John Jones QC Memorial Fund. Donations will be used to support his family and perpetuate his work.

Contributor Geoffrey Robertson QC, Doughty Street Chambers