The courtroom adjudicator stood up abruptly to interrupt a Ukrainian lawyer as he rapidly ran through the lengthy indictment of a Russian occupation official. A hundred Ukrainian lawyers, alongside British instructors and diplomats, adjusted their headsets, trying to follow the torrent of translated legal argument.
‘I ask you again, please, to slow down,’ the female adjudicator said. ‘If you keep speaking at these speeds, the translation team won’t make it to the end of the day.’ The Ukrainian prosecutor nodded, adjusted his glasses, and returned to the indictment.
Henadii Ivanovych Yazov, the First Deputy Governor of the occupied Kherson Oblast, stood accused of helping implement the Russian-imposed policy of coercing and deporting the occupied territory’s local population. The prosecution argued Yazov used administrative pressure, including passport restrictions, the deprivation of access to basic utilities and deportation decrees, to force civilians either into compliance with Russian rule or out of occupied regions altogether.
Future prosecutions would only survive international scrutiny if they are seen to be fair
The defence wasted no time in objecting: the evidence was insufficient to prove Yazov was carrying out a Russian state policy of forced deportation. They argued this merely showed an occupying administration attempting to govern hostile territory during wartime. The British advisers then stopped the proceedings to dissect the arguments.
The trial was fictional, as was Yazov, but the allegations were not. The real-life officials that Yazov represents could soon face prosecution.
Over two days in Kyiv, British-funded legal advisers staged a rehearsal for the crimes-against-humanity cases Ukraine expects to begin bringing against Russians and their collaborators in the near future. Ukraine’s Office of the Prosecutor General says it is currently investigating 45 occupation officials connected to such allegations and believes one of those cases may soon reach court.
Unlike many of the war crimes cases already pursued against individual Russian soldiers, the mock trial being rehearsed in Kyiv focused on a far more difficult question: how to prove a systematic policy of deportation enacted by the Russian state.
‘You can’t have this level of war crimes, so widespread and systematic, without it amounting to crimes against humanity,’ said Wayne Jordash, a British human rights barrister advising the Ukrainian prosecutor’s office, who oversaw the exercise.
Ukraine has prosecuted hundreds of war crimes cases since Russia’s full-scale invasion in February 2022. But prosecutors have only recently begun preparing crimes-against-humanity cases after the country aligned its criminal code more closely with the Rome Statute towards the end of 2024. Unlike isolated war crimes, crimes against humanity require prosecutors to prove attacks against civilians were carried out as part of a broader state or organisational policy.
The challenges are immense: gathering evidence from occupied territories, ensuring fair trials in absentia, proving links between local occupation officials and central Russian policy, and building cases capable of surviving international scrutiny while the war itself continues. Jordash said there was ‘barely any precedent’ for investigating crimes against humanity during an active war.
Throughout the mock proceedings, defence lawyers repeatedly pushed back against attempts by prosecutors to connect local actions to broader Kremlin policy. When the prosecutors pointed to Telegram posts in which the fictional Yazov described anti-Russian protests as ‘provocations’, arguing they demonstrated alignment with wider Russian policy, defence lawyers countered that the posts merely reflected his personal political sympathies rather than illegal acts. ‘An administrative role does not equate to criminal intent,’ one defence lawyer argued.
At another stage, lawyers spent hours debating whether intelligence gathered inside occupied territory could ever be admissible in court without exposing their sources to Russian retaliation. British advisers compared the dilemma to the use of covert operatives in organised crime investigations in the UK, where evidence can sometimes be presented through closed proceedings and special counsel arrangements compliant with European human rights law.
Each section of the exercise was followed by lengthy discussions between the British advisers and Ukrainian lawyers over how arguments could be tightened, challenged or narrowed to what could actually be proven in court.
The rehearsal, however, was as much about instructing the defence as the prosecution. British advisers repeatedly stressed that future prosecutions would only retain legitimacy if Russian defendants, even absent ones, were defended robustly, a principle lawyers refer to as ‘equality of arms’.
‘Everybody is entitled to a competent defence,’ said Sir Howard Morrison, a former International Criminal Court (ICC) judge now advising Ukraine’s Office of the Prosecutor General. ‘If it’s not fair, it’s not a trial, it’s just a process.’
In a country under daily attack, balancing accountability with due process presents obvious tensions. British advisers repeatedly returned to the same point throughout the exercise: future prosecutions would only survive international scrutiny if they are seen to be fair. ‘I think prosecutors see the production of fair trials as their contribution to the fight,’ Jordash said.
Ukraine and its European allies are simultaneously pursuing accountability through a separate international track. President Volodymyr Zelensky, with the backing of the Council of Europe, is attempting to establish a ‘special tribunal for the crime of aggression’ aimed at prosecuting senior Russian political and military leaders for launching the invasion itself. But even optimistic officials privately acknowledge that any international tribunal capable of prosecuting senior Russian leaders may take years before a courtroom is operational.
British support for the mock trials reflects a broader calculation that, while international tribunals may take years to materialise, Ukraine’s domestic courts are likely to deliver the first meaningful prosecutions. Britain has supported Ukraine’s war crimes investigations since 2014 through training, forensic support, investigative advisers and funding for legal teams working alongside prosecutors.
Faced with more than 229,000 registered alleged war crimes, Ukrainian prosecutors have already begun discussing which cases can realistically be pursued. ‘Clearly, we cannot investigate all crimes simultaneously with equal effectiveness,’ Taras Semkiv, a senior official at Ukraine’s Office of the
Prosecutor General, said.
Priority is being given to cases involving mass casualties, attacks on critical infrastructure, environmental destruction and investigations linked to the ICC or a future tribunal. Prosecutors are already gathering material intended for any future tribunal investigating Russia’s crime of aggression.
A few minutes before the lawyers were due to deliver their closing statements – a conclusion that cannot be reported publicly over concerns that Russia is monitoring Ukraine’s prosecutorial preparations – participants were reminded once again of the reality surrounding the proceedings. An air raid siren sounded outside the conference room, and several participants reached into their pockets to check the seriousness of the attack on their phones. A Shahed drone was flying over the outskirts of Kyiv. They finished their coffees and headed back into the courtroom. The task of proving Russia’s crimes cannot wait for the war to end.
Comments