A years-long review into the sentencing of convicted Libor rigger Tom Hayes has been “derailed”, according to someone close to the case, as the pandemic sparked an impasse between investigators and prosecutors over access to critical case information.

The Criminal Cases Review Commission, an independent body responsible for investigating suspected miscarriages of justice, was unable to access key documents on IT systems run by the UK’s Serious Fraud Office for months due to the lockdown, according to people in the Hayes camp with knowledge of the problem.