The King’s private funds will not be used to finance Andrew Mountbatten-Windsor’s legal action against Thames Valley Police, it is understood.

The former Duke of York is taking legal action against the force in a bid to quash search warrants which led to his arrest, with a private High Court hearing due to take place on Thursday at 2pm before Mr Justice Hilliard.

Mr Mountbatten-Windsor was arrested on his 66th birthday on suspicion of misconduct in public office following allegations he shared sensitive information with late sex offender Jeffrey Epstein during his time as the UK’s trade envoy.

He has always strenuously denied any wrongdoing.

Mr Mountbatten-Windsor receives an annual stipend provided by the King from the monarch’s private funds. But a Palace source said it has been made clear that these monies should not be used to fund the Judicial Review.

The source told the Press Association that Andrew’s legal defence was a matter for him and his lawyers and that Buckingham Palace has no role in determining its strategy or actions.

The High Court is set to consider a bid by the force to restrict access to certain documents. Thames Valley Police will set out its position on the potential impact releasing these documents could have on its criminal investigation.

The former Duke of York was interviewed under caution following his arrest on 19 February before being released under investigation. Police began their searches of the properties on the same day, with the force confirming on 24 February that they had ended.

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 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.

A Thames Valley Police spokesperson toldpreviously: “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.”