Andrew Mountbatten-Windsor has won his legal challenge against Thames Valley police over search warrants that led to his arrest.

The former prince brought a judicial review of the legality of the force’s actions and those of the central criminal court, which granted the warrants.

On Thursday, Mr Justice Hilliard, sitting at the high court in central London, said Thames Valley police had conceded that it obtained the search powers under the wrong statutory provision and ruled that the warrants were unlawful.

The warrants were issued by the recorder of London, Mark Lucraft KC, at the Old Bailey and Mountbatten-Windsor was subsequently arrested on 19 February, his 66th birthday, on suspicion of misconduct in public office.

The arrest followed information that emerged from the Jeffrey Epstein files. It was alleged that when Mountbatten-Windsor was the UK’s trade envoy he shared sensitive information with Epstein, a convicted child sex offender.

Police began searching the former Duke of York’s residence on the Sandringham estate, and his former Windsor home, Royal Lodge, on the same day as his arrest.

Hilliard said the search warrants were quashed but police had made an application, which would be heard next year, to retain the property seized, on the basis that it would have been lawful to seize it under a different statutory provision.

The judge said: “The fact that the search warrants were quashed does not bring the investigation to an end or mean that the whole of the investigation is unlawful.”

Late last year, King Charles stripped his brother of his right to be a prince and of his dukedom over his association with Epstein.

He receives an annual stipend, the amount of which has not been disclosed, from King Charles’s private funds, but a palace source told reporters it had been made clear this should not be used to fund the judicial review.