Sadiq Khan has agreed to have his text messages and emails searched as part of a High Court legal battle with the US tech firm Palantir, after he blocked the company from working with the Metropolitan Police. The London mayor stepped in to halt a proposed £50m deal in May, prompting Palantir to sue his office, and the dispute matters because it pits City Hall's procurement objections against a major AI contractor with ties to the Israeli military and the Trump administration's immigration enforcement efforts.

At a preliminary hearing, the court heard that Khan and more than a dozen other officials from the Mayor's Office for Policing and Crime and the Greater London Authority will be classed as "custodians", meaning their digital communications will be searched and disclosed to Palantir. Khan's lawyers said they had not originally deemed this necessary but relented after Palantir persisted; Sarah Brown, Khan's former communications director who now works for Andy Burnham in Downing Street, will also have her correspondence searched, after Palantir claimed press briefings she "initiated" cited concerns about the firm's values and ethics. Mopac had blocked the two-year deal citing a "clear and serious breach" of procurement rules, saying only one supplier had been seriously considered; the date range for the searches has yet to be set, and Mopac is reportedly seeking Palantir's own internal documents, which the firm is said to be resisting.