One error in a warrant application leaves police fighting to keep the Mountbatten-Windsor evidence

The defect was in the first step, and everything after it depended on that step. According to The Independent's report of the hearing, the February warrant did not cover material gained or created in the course of a trade, profession or office and expected to be confidential ^[18]. Mr Justice Hilliard said the presence of such material was "inherent" in a misconduct in public office case, so the application was made in error ^[18]. The inquiry concerns whether a former UK trade envoy shared sensitive information with Jeffrey Epstein ^[9]. On the judge's reasoning, material of that kind was always going to be among what officers took ^[18]. He said a "significant error" in the application was "enough to render the warrants, the searches and the material seized unlawful" ^[1].

The record is split on who made the mistake. Hilliard said significant errors were made both by Thames Valley Police in applying for the warrants and by the judge who granted them, ABC News reported ^[2]. The force's statement after the ruling puts the fault on the court. "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," a spokesperson said ^[8]. "We ensured the court was presented with all the necessary information and paperwork to inform their decision, following the correct legal processes throughout," the spokesperson added ^[23].

Nick Vamos, a criminal lawyer, said it was "embarrassing" that police had made an error in a case this prominent ^[20]. "This should have gone under so many noses before it went to court that it's really amazing that they still managed to make a basic error," he told the BBC ^[20].

How far the error reaches is a separate question, and English law gives it a narrow answer. Mark Stephens, a lawyer not involved in the case, said the ruling "opens a door to Andrew Mountbatten-Windsor's lawyers to start to chisel away at some of the fruits of that unlawful warrant" ^[11]. He also set it against the American rule. "For example, in America, if you have the fruits of an unlawful warrant, then all that evidence is out. But that's not the case in the U.K., so we've got a few more rounds to go here," Stephens said ^[13]. Danielle Reece-Greenhalgh, a partner at Corker Binning, said: "The question of whether and how unlawfully obtained evidence can be used centres on whether its admission would have such an adverse effect on the fairness of the proceedings that the court ought not to admit it." ^[14] Hilliard himself said "the fact that the search warrants were quashed does not bring an investigation to an end, or mean that the whole of the investigation was unlawful" ^[3].

I think the main cost of the error is time. The warrants were executed on the day of the arrest, February 19 ^{[7] [12]}. The High Court formalised the agreement to quash them on July 22 ^[4], about five months later ^[22]. Hilliard has yet to rule under the provision that lets police retain unlawfully seized property for evidence ^[15].

Any organisation that runs a process like this one faces the same choice: spend time reviewing an authorising document before it is signed, or spend time in litigation after it fails. The concession in July settled the argument over the warrants ^[4]. It started a second one over the evidence, and Mountbatten-Windsor is opposing the force's bid to keep it ^[6].