High Court Rules Search Warrants Used at Andrew Mountbatten-Windsor's Homes Were Unlawful as Police Investigation Continues

Thames Valley Police has conceded that the search warrants used to raid the homes of Andrew Mountbatten-Windsor at the time of his arrest earlier this year were unlawful, the High Court was told on Thursday. The force accepted that the initial court decision to issue the warrants under the specific piece of legislation relied upon was incorrect, a development that casts a legal shadow over one of the most closely watched criminal investigations in recent British history.

The ruling, delivered by Judge Mr Justice Hilliard, confirms that Mountbatten-Windsor and the police had reached an agreement that the warrants were unlawful. The former prince, who was arrested on 19 February on suspicion of misconduct in public office, had launched a legal challenge over the legality of the search warrants shortly after officers descended on his properties.

Despite the setback for the force, the judge was careful to stress that the ruling does not signal the end of the broader investigation. "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," Mr Justice Hilliard said. His remarks make clear that while the procedural mechanism used to enter and search the properties was flawed, the underlying inquiry into Mountbatten-Windsor's conduct remains live and legally valid.

Items seized during the raids continue to be held by Thames Valley Police, and a further hearing is expected in 2027 to determine whether the material can ultimately be used as evidence. Mountbatten-Windsor is opposing the force's bid to retain the seized items, setting the stage for a prolonged legal battle over the future of the evidence.

The dispute centres on a technical but consequential distinction in English law. Thames Valley Police had applied for search warrants under sections eight and nine of the Police and Criminal Evidence Act 1984 at a hearing at the Central Criminal Court the day before the search was carried out. That court determined that only section eight warrants were necessary and granted them on that basis. A subsequent legal challenge, however, established that the court should have issued the warrants under section nine instead. The force has now accepted that the "initial court's decision to issue warrants under the specific piece of legislation used was incorrect."

The distinction matters because section nine warrants are designed to address situations involving sensitive material. Strict legal safeguards prevent police from automatically seizing protected material without first considering in advance whether they need to take it. Such material can include advice from a suspect's lawyer or documents that do not genuinely belong to the suspect, such as copies of confidential work-related papers belonging to an employer. Where officers encounter this kind of material during a search, the expectation is that it should be returned rather than used in an investigation. The category of warrant granted in this instance did not account for the possibility that protected material might be seized.

Nonetheless, the law does allow police to seize such material, or potentially retain it following an error, provided they satisfy additional legal tests. Thames Valley Police must now persuade a judge that the material is likely to be of substantial value to its investigation. The next stage in the dispute will be a behind-closed-doors hearing examining whether the force can retain the seized material under alternative powers intended for precisely this kind of scenario.

In explaining why the police could continue to hold the former prince's items, Mr Justice Hilliard offered a pragmatic rationale. "There would be little point in handing property back if it could then simply be lawfully seized under some other provision," he observed. The comment underscores the court's apparent view that the procedural error, while significant, should not automatically result in the return of material that could lawfully be obtained through a corrected legal process.

A Thames Valley Police spokesperson said the agreement that led to the quashing of the warrants related specifically to a decision made by the court regarding the legal basis for the searches, and was not a judgment on the ongoing investigation. The spokesperson added that the force had ensured the court was presented with all necessary information and paperwork to inform its decision, following correct legal processes throughout. The force reiterated that its investigation into alleged misconduct in public office by a man in his 60s from Norfolk remains ongoing, and that it continues to pursue all reasonable lines of enquiry to progress the case effectively and fairly.

The investigation has its origins in documents published by the US Department of Justice, which raised suspicions that Mountbatten-Windsor had forwarded confidential information to the convicted sex offender Jeffrey Epstein when he served as a UK trade envoy in 2010. He has consistently denied any wrongdoing, both in relation to Epstein and more broadly, and he denies the misconduct in public office allegation that led to his arrest.

Mountbatten-Windsor's legal team has pursued a judicial review challenging the actions of the force's chief constable and the Central Criminal Court in the build-up to his arrest. That challenge has now yielded a significant procedural victory, even as the substantive investigation presses ahead. Legal experts note that unlawful warrants do not necessarily invalidate an entire investigation, particularly where the police can demonstrate that seized material could be lawfully obtained through other statutory routes.

The case raises broader questions about the safeguards surrounding searches of high-profile individuals and the importance of selecting the correct legal framework before intrusive powers are exercised. The requirement to consider sensitive material in advance is intended to protect privileged communications and third-party interests, and the failure to apply the correct warrant category has now been formally acknowledged by the force.

For Mountbatten-Windsor, the ruling represents a partial success in his efforts to challenge the manner of the police operation against him. Yet the practical consequences remain uncertain, with the seized documents and electronic devices still in police hands and the question of their admissibility unresolved. The 2027 hearing will be pivotal in determining whether the evidence gathered during the raids can form part of any future prosecution.

As the legal wrangle continues, the investigation itself shows no sign of concluding. Thames Valley Police has made clear it intends to press forward, and the courts will now be asked to decide how material obtained through flawed warrants should be managed. The outcome could shape not only the fate of this particular inquiry but also the standards applied to searches in sensitive criminal cases more widely.