Ben is a leading junior specialising in extradition and international criminal law, with particular expertise in complex, sensitive and politically significant cases. He acts principally for requested persons at first instance and on appeal and has an established track record in significant High Court litigation. His cases frequently involve difficult human-rights issues, foreign law, expert evidence and investigation overseas, including proceedings concerning prison conditions, mental health, fair-trial rights, abuse of process and allegations of political or state mistreatment.
His wider practice encompasses international criminal law, business crime and cross-border investigations, sanctions, INTERPOL and public and international law. He is a member of the Attorney General’s Civil B Panel and the SFO Advocate Panel and has substantial experience advising government and acting in proceedings before international criminal courts and tribunals.”
Ben is an established specialist extradition practitioner who appears regularly at Westminster Magistrates’ Court and in the Administrative Court. He acts as sole counsel, leading junior and led junior in serious and complex proceedings, with a predominantly defence practice.
His particular expertise includes cases concerning:
He has substantial experience identifying and working with foreign lawyers, prison experts, psychiatrists and other specialist witnesses, as well as obtaining evidence directly from proceedings and institutions abroad. His advisory practice also extends beyond contested English extradition proceedings to INTERPOL notices, international sentence transfer, import extradition and challenges or negotiations capable of resolving warrants overseas.
Ukraine v Artem Dmytruk (2026, unreported)
Led by Edward Fitzgerald KC for a serving Ukrainian Member of Parliament in politically sensitive extradition proceedings arising from the war in Ukraine. Chief Magistrate refused extradition following findings concerning previous ill-treatment by Ukrainian state agents. Proceedings involved extensive expert evidence and attracted significant international attention.
ZA v Romania [2025] EWHC 595 (Admin); [2024] EWHC 1269 (Admin)
Sole counsel for the appellant. The decision confirms that oppression in mental-health cases is not confined to a high risk of suicide, particularly where psychiatric injury is linked to serious abuse previously suffered in the requesting state.
Mikelic v Croatia (No 1) [2025] EWHC 208 (Admin); Mikelic v Croatia (No 2) [2025] EWHC 1285 (Admin)
Sole counsel for the appellant.The High Court held that cogent evidence concerning the Zagreb Diagnostic Centre rebutted the usual presumption of Convention compliance and that a facility-specific assurance was required.
Stojcevic v Croatia [2024] EWHC 1477 (Admin)
Leading Tihomir Mak, appeal allowed in a case involving war crimes arising from the conflict in former Yugoslavia. The defence obtained material directly from the Croatian court file which contradicted aspects of the requesting authority’s evidence and demonstrated substantial unexplained delay.
Dobrowolski v Poland [2023] EWHC 763 (Admin), [2023] ACD 67, CLW/23/24/10
Sole counsel for the appellant in a successful High Court appeal concerning the treatment of Polish early-release provisions within the Article 8 proportionality assessment. Dobrowolski became the vehicle through which the Supreme Court resolved conflicting High Court authority in Andrysiewicz v Poland [2025] UKSC 23.
Rymarski v Poland [2023] EWHC 3389 (Admin)
Sole counsel in a successful appeal concerning abuse of process. The High Court held that materially identical fresh extradition proceedings could not be used to circumvent the statutory appeal regime and obtain an improper litigation advantage.
Ben has substantial experience in international criminal and humanitarian law, including major defence cases before international criminal courts and tribunals. He has worked in complex, document-heavy investigations and proceedings in Africa and Southeast Asia, including interviewing sensitive witnesses and working with military, communications, financial and other experts.
He is appointed to the List of Counsel of the International Criminal Court, the List of Counsel of the Kosovo Specialist Chambers, and the List of Legal Consultants of the Extraordinary Chambers in the Courts of Cambodia.
The Prosecutor v Uhuru Kenyatta – International Criminal Court
Long-term member of the defence team representing the former President of Kenya on charges of crimes against humanity. Ben was involved in work identifying significant defects in the prosecution investigation. The prosecution ultimately withdrew all charges and the proceedings were terminated.
The Prosecutor v Dominic Ongwen – International Criminal Court
Legal consultant to the defence of the first former child soldier to stand trial before the ICC. The case raised novel questions concerning criminal responsibility and duress in circumstances where the accused was alleged to have been both perpetrator and victim of crimes committed by the Lord’s Resistance Army.
Case 004/02 – Ao An – Extraordinary Chambers in the Courts of Cambodia
Legal consultant to the defence of an alleged former Khmer Rouge leader facing allegations including genocide and crimes against humanity. The proceedings were ultimately terminated after the Chambers were unable to establish jurisdiction following a lengthy investigation.
Ben’s business crime practice focuses on complex cross-border investigations, fraud, corruption and sanctions. He has advised corporate clients and investigating authorities in matters involving the Serious Fraud Office, Financial Conduct Authority, US Department of Justice and Office of the Attorney General of Switzerland, and has experience of investigations spanning different jurisdictions and legal systems.
He has particular experience of large-scale, document-heavy investigations and disclosure. For several years, Ben was instructed by the Serious Fraud Office to lead a disclosure team in a substantial prosecution under the Bribery Act 2010 and Proceeds of Crime Act 2002. He is a member of the SFO Advocate Panel (C Panel).
Ben also advises on sanctions and related international measures. His previous work has included advising on and challenging designations imposed under UN, UK, US and EU sanctions regimes.
His extradition and international criminal law practices also give him particular experience in matters where business crime overlaps with cross-border investigations, mutual legal assistance, INTERPOL, extradition and sanctions.
Ben is a member of the Attorney General’s Civil B Panel of Junior Counsel to the Crown. His public law practice draws particularly upon his experience of government decision-making, international law, human rights and cases involving the exercise of state power.
Ben previously spent the equivalent of six months embedded full-time within the FCDO’s Foreign Relations Team in Whitehall, advising the Department and government ministers on public and international law. His work included legal issues arising from the International Law Commission’s Draft Articles on Prevention and Punishment of Crimes Against Humanity, as well as advice to the FCDO’s Consular Directorate on questions of international law.
His extradition practice also involves substantial public law litigation in the Administrative Court, including questions of procedural fairness, human rights, the legality of state action and the limits of judicial and executive decision-making. His reported cases include Celczynski v Poland [2019] EWHC 3450 (Admin), [2020] 4 WLR 21, which considered the scope of the High Court’s judicial-review jurisdiction in extradition proceedings.
Defence Extradition Lawyers Forum
As Chair, Ben has represented the specialist defence extradition profession in engagement with government, Parliament, the CPS, HMCTS and Westminster Magistrates’ Court. In 2025-6, he led DELF’s response to proposed amendments to the Extradition Act 2003, including the preparation of briefing material and direct engagement with ministers and parliamentarians during the passage of the Crime and Policing Bill.
International Bar Association – War Crimes Committee
Vice Chair, 2024–2025.
“Ben’s legal knowledge and ability to digest the most complex legal arguments is impressive. His personable and empathetic approach is always received warmly by clients.” - Chambers and Partners, 2026 (Extradition)
“Ben Joyes is able to see to the heart of a case and understand which points will win. He has an enviable track record of success.” - Chambers and Partners, 2026 (Extradition)
“Ben is really impressive; he has been instrumental in building and growing [the practice]. He is all over the details, looks for new angles on how to present a case and does the hard work.” - Chambers and Partners, 2026 (Extradition)
“Ben is exceptionally meticulous and thorough. He possesses a great legal mind.” - Chambers and Partners, 2026 (Extradition)
Ben is someone who really fights his client's corner, and he raises every issue one can raise. He is really committed to leading the case for his clients and is personable and a good advocate. - Chambers and Partners, 2026 (Extradition)
“Ben is a regular practitioner in the extradition field and is a diligent and hard-working junior with a good base of defence work. He has a thorough grounding in extradition law and a lieable advocacy style which endears him to courts and opponents.” - Legal 500 2026 (Extradition)
“Hard-working and experienced – regularly appears in the High Court.” Legal 500 (International human rights and criminal law)
“His advocacy is brilliant. He is becoming one of the standout practitioners at the extradition Bar.” - Legal 500, 2025
