Andrew Mountbatten-Windsor is taking legal action against Thames Valley Police in a bid to quash search warrants which led to his arrest.
The former Duke of York has been granted permission to challenge whether the force acted lawfully in February.
Mr Mountbatten-Windsor was arrested on his 66th birthday on suspicion of misconduct in public office following allegations he shared sensitive information with Jeffrey Epstein during his time as the UK’s trade envoy.
A private High Court hearing will take place on Thursday at 2pm before Mr Justice Hilliard, a judicial spokesperson said.
A Thames Valley Police spokesperson told The Independent: “Whilst our investigation into misconduct in public office continues, we are engaged in legal proceedings in relation to warrants previously obtained from the Central Criminal Court. As these legal proceedings are currently ongoing, it would be inappropriate for us to comment further.”
A judge at the Old Bailey issued warrants which allowed police to raid the former duke’s residence on the Sandringham Estate and his former Windsor home, Royal Lodge.
The hearing will begin in private concerning a bid by Thames Valley Police to restrict access to court documents, the judicial spokesperson said. It is unknown whether Mr Mountbatten Windsor will attend the hearing.
The former Duke of York was interviewed under caution following his arrest on 19 February before being released under investigation.
The legal definition of misconduct in a public office can include a wide range of conduct – including sharing confidential financial information, financial misconduct, wilful neglect of duty, and sexual misconduct.
It also covers corruption and improper interference, conflict of interest, perverting the course of justice, dishonesty or fraudulent conduct, and misconduct leading to personal gain.
The King stripped his brother of both his right to be a prince and his dukedom over his association with Epstein in October last year.
The Independent has contacted Buckingham Palace and Mr Mountbatten-Windsor for comment.