Kostin told the IBA’s executive director Mark Ellis that his office had been working relentlessly to bring those responsible for crimes of aggression and genocide to account. 

The session provided him with a platform to set out Ukraine’s case for the need for the establishment of a special tribunal akin to the Nuremberg trials, which brought Nazi war criminals to account after the Second World War. 

Backed by prominent international lawyers, including the UK’s Philippe Sands KC, Ukraine has been garnering international support for such a tribunal, which would operate outside the remit of the International Criminal Court. 

Kostin said his office and partners across the world had been gathering evidence of alleged war crimes to ensure they have a strong case to bring forward prosecutions of the perpetrators.

“I believe that a special tribunal should be created and should be of international dimension. The crime of aggression is an international crime, and so to punish those who started it, the response should be international. 

“With such a tribunal, Ukrainian victims will not only feel vindicated, but it will also create a deterrent effect for other potential aggressors. The UN’s Security Council will not serve as a sufficient instrument due to veto rules. We need an international judicial instrument.” 

The plan for a special tribunal has received the backing of the European Parliament, and several other nations, although some commentators fear it could undermine the work of the International Criminal Court – whose chief prosecutor, Karim AA Khan KC, will be interviewed by Ellis on Wednesday at the IBA conference. 

“Punishment for the crime of the aggressor would be the only justice for Ukrainian civilians drafted and killed in this war,” said Kostin. “If we lose, the frontline will go beyond Ukraine, and it will give impunity for the aggressor to continue.” 

Kostin insisted that the judicial process must be fair and impartial throughout, adding that his office has been training prosecutors, judges and defence attorneys from the legal aid system to be impartial for the sake of justice. 

The Prosecutor General also discussed his domestic agenda. Responding to a question from the floor, he said he had implemented a three-point plan to “clean up” domestic problems including corruption at all levels, the illegal influence of oligarchs who, according to him, “feed this corruption” and are “squeezing the Ukrainian economy”, and organised crime relating to cocaine and heroin production and trafficking in particular. He added that Ukrainian authorities and European authorities had held several joint operations in Spain, Romania and Ukraine to prevent such activities.

This article first appeared in the daily newspaper for the IBA Annual Conference 2023, which is published in partnership with The Global Legal Post