“Throughout my career I have been fighting corruption and fraud, and for ethics and integrity,” Biro wrote in his application letter for the post of president in October 2022.

According to a statement released by the chief prosecutor, in addition to his official vehicle, Biro rented a second luxury car, racking up a 14m Hungarian forint (€34,000; £29,000) bill.

Hungarian media reports allege that office funds were used to renovate his luxury home, and build a fence several hundred metres long around it.

Starved of EU funds, with the Hungarian currency losing value and a sharp rise in annual inflation to 4.6% last month, the Hungarian economy is in trouble.

Critics of the government believe Ferenc Biro may be right – that Viktor Orban is trying to sacrifice one of his chess pieces, in order to access badly needed cash.

Biro has hit back against the investigation in a statement of his own.

“Today they have specifically attacked my person and through this they have sought to make the operation of the Integrity Authority impossible,” he said on Thursday night.

“Our organisation has always operated and continues to operate to the highest ethical and legal standards.”