A $4.2bn (£3.2bn) fraud trial involving the former owners of Ukraine’s largest bank has been delayed by a year after the High Court ruled the defendants could not have a fair trial because of the Russian invasion.

Privatbank alleges Igor Kolomoisky and Gennady Bogolyubov, who were among the founders of the Ukrainian lender in 1992, and a number of related companies orchestrated the fraudulent misappropriation of almost $2bn through sham loans in 2013 and 2014, which is denied.

The trial of Privatbank’s claim was due to be heard over several weeks from June, but lawyers for the two men said at a pre-trial review this week that the war in Ukraine made it ‘impossible for a fair trial to take place’ this year.

Clare Montgomery QC, for Bogolyubov, said her client is ‘regularly having to go to a shelter when the air raid sirens sound’ and is also ‘concerned that he will be targeted by the Russian state because of his relationship with Mr Kolomoisky’, who she said is ‘a known enemy of President Putin’.

Bogolyubov’s solicitors have only been able to speak to him twice since the start of the war and he has been ‘unable to devote time to preparing his case for trial’, she told the court.

Mark Howard QC, for Kolomoisky, said it was impossible for his client to prepare for trial in a ‘war zone’, asking: ‘How could people in Ukraine possibly give evidence?’

Privatbank asked the court to wait until May to decide whether to adjourn the trial, but Mr Justice Trower ruled it should be delayed and suggested a possible trial date of June 2023.