Andrew Mountbatten-Windsor, the younger brother of King Charles III, has launched a legal challenge against Thames Valley Police over his arrest earlier this year in connection with documents released by the United States Department of Justice on the late sex offender Jeffrey Epstein.

The former prince was arrested on 19 February, his 66th birthday, on suspicion of misconduct in public office, over allegations that he shared sensitive government documents with Epstein while serving as Britain's special representative for international trade between 2001 and 2011. Detectives questioned him for eleven hours before releasing him under investigation. Officers also searched two of his residences: a property on the Sandringham estate in Norfolk and his former home, Royal Lodge in Windsor.

According to the Daily Telegraph, Mountbatten-Windsor has now lodged a judicial review claim with the High Court in London, asking a judge to determine whether the police force acted lawfully. The challenge centres on the search warrants that authorised the raids. A judicial spokesperson confirmed that a claim had been filed and that a hearing was scheduled. It was reported that the proceedings mark the first time in nearly four centuries that a member of the British royal family has contested the lawfulness of criminal proceedings against them.

Thames Valley Police confirmed it was engaged in legal proceedings relating to warrants previously obtained from the Central Criminal Court, while stressing that its investigation into misconduct in public office was continuing. A force spokesman declined further comment while the proceedings were ongoing.

The arrest in February was the most dramatic escalation yet of the long-running Epstein saga for the British monarchy. It made Mountbatten-Windsor the first senior royal to be placed under arrest in living memory, a development that underscored how far deference towards the institution has eroded in recent years. He has denied any wrongdoing in relation to Epstein and has said he regrets their friendship.

The allegations emerged when the US Justice Department released millions of pages of documents from its investigation into Epstein's sex-trafficking network and his circle of wealthy and powerful associates. Material within those files suggested that Mountbatten-Windsor had passed confidential information to Epstein during his trade envoy years. He has not been charged, and the investigation remains active.

The controversy has hung over him for more than a decade. He was forced to step back from official royal duties in 2019 following his disastrous BBC Newsnight interview about his friendship with Epstein, and last October his older brother stripped him of his remaining titles and honours amid fresh revelations about the relationship. Buckingham Palace has made no public comment on the latest legal action.

Legal observers say the judicial review faces a steep climb: courts give police considerable latitude in the early stages of an investigation, and the threshold for finding an arrest or search warrant unlawful is high. But whatever the outcome, the sight of a former prince suing the police force that arrested him ensures the case will remain one of the defining British scandals of the year.