Scotland Yard said the incident was still subject to an ongoing investigation, but that no arrests had been made and there had been few leads to pursue.

Mr Adamescu’s father was recently moved from his prison cell to a hospital ward to receive treatment for sepsis, leading to fears for his long-term well-being.

Mrs Constantinescu, a marketing specialist, said: “Dan is in a life-threatening condition and held in intensive care after a septic shock. We don't know if he'll survive. His health has been ruined by the intentional mistreatment he's received at the hands of the Romanian state. Alexander will be similarly tortured. I fear for his life if he's to be returned."

She added: “As a wife and mother, I try to remain positive about the outcome of the extradition attempt, but fear greatly for Alexander and our children who will potentially be separated from both their father and grandfather in the future. I do hope that the new Romanian government who has promised to uphold the rule of law will keep its promise.”

The family’s supporters claim former-Communist elements within Romania’s security services fabricated a bribery case against the Astra insurance company run by Mr Adamescu Snr, which had grown to become the country’s largest.