Thames Valley Police has accepted that the search warrants it used to search Andrew Mountbatten-Windsor’s homes earlier this year were unlawful, the High Court has heard.

The force said it accepted that the “initial court’s decision to issue warrants under the specific piece of legislation used was incorrect” before they searched the former prince’s properties on 19 February.

Andrew was arrested by Thames Valley Police on suspicion of misconduct in public. He denies any wrongdoing.

The criminal investigation is ongoing and the items seized in the raids on his homes in Norfolk and Berkshire will remain in police custody while his legal challenge over this material continues.

Andrew’s lawyers have used a judicial review to challenge the actions of the force’s chief constable and the Central Criminal Court.

His arrest in February arose after the US Department of Justice published documents which suggested he had forwarded confidential information to the convicted sex offender when Mountbatten-Windsor was a UK trade envoy in 2010.

He has consistently denied any wrongdoing in relation to Epstein.

The court heard on Thursday that Thames Valley Police took possession of documents and electronic devices when they raided Andrew’s homes.

The conditions for the warrants were that there had to be reasonable grounds for believing that any documents used for business or in a paid or unpaid role in which an undertaking of confidence had been given should not be seized.

The force now accepts the judge who granted the warrants could not have been sure of this.

A Thames Valley Police spokesperson said: “The agreement that led to the quashing of the warrants relates specifically to a decision made by the court regarding the legal basis for these and is not a judgement on our ongoing investigation.

“We ensured the court was presented with all the necessary information and paperwork to inform their decision, following the correct legal processes throughout.

“We accept the position that the initial court’s decision to issue warrants under the specific piece of legislation used was incorrect and therefore these must be legally quashed.

“Legal proceedings are currently ongoing to decide how material seized during the searches will be managed and whether we can lawfully retain it in support of our ongoing investigation.”

The force said its “investigation into alleged misconduct in public office by a man in his 60s from Norfolk remains ongoing, and we continue to pursue all reasonable lines of enquiry to effectively and fairly progress this investigation”.