Winterkorn’s trial was due to begin on September 16, but may now be delayed, as he has a hip operation scheduled. The Braunchschweig Regional Court is weighing whether to postpone Winterkorn’s case until a later date.

That would mean the September 16 date would only apply to four other defendants, court spokesperson Stefan Bauer-Schade said, according to Business Insider media outlet.

It remains unclear when the decision will be made about a possible postponement.

Alongside Winterkorn, four others are accused, some of whom are former VW executives.

They are to be charged with commercial and gang fraud in connection with the emissions manipulations on millions of cars that triggered the diesel crisis in 2015.

Winterkorn resigned more than five and a half years ago after the scandal came to light in the US. He claims he only learned of the manipulations shortly before they became public knowledge.

The revelation of the nitrogen oxide manipulations in diesel engines in the US in 2015 triggered legal cases worldwide. Volkswagen admitted its guilt in principle to the US Department of Justice for deceiving customers and authorities.