High Court upholds Met Police WhatsApp deletion policy in BB v Commissioner of Police of the Metropolis

The High Court has dismissed a judicial review challenge to Metropolitan Police guidance requiring officers to activate WhatsApp's disappearing message function, set to delete conversations after ninety days, finding across all four grounds of challenge that the policy was lawful.

Mr Justice McKendrick heard the claim brought by a defendant in ongoing Crown Court proceedings, referred to as BB for anonymity purposes, who argued the guidance risked the destruction of material relevant to criminal investigations before its evidential significance could be assessed. The challenge arose from BB's own prosecution for coercive and controlling behaviour and breach of a non-molestation order, during which the officer in the case, Detective Constable Archer, had communicated with the complainant via WhatsApp.

The guidance, introduced in 2023 alongside the wider rollout of WhatsApp on Met Police devices, instructs officers to keep the ninety day disappearing message function switched on for all conversations, while directing that evidential or CPIA-relevant material must not be shared through instant messaging at all, and must instead be exported and uploaded to the force's evidence repository if received unexpectedly.

On the first ground, that the guidance unlawfully sanctioned breaches of disclosure obligations under the Criminal Procedure and Investigations Act 1996, the judge applied the Supreme Court's framework in R (A) v Secretary of State for the Home Department for assessing whether a policy misstates the law. He found the claimant had not established that the guidance was issued pursuant to any duty to provide legal advice, nor that it purported to offer a comprehensive account of disclosure obligations. Read fairly, the guidance directed officers away from using WhatsApp for evidential material and provided a mechanism for export where such material was unexpectedly received, meaning it did not misstate the applicable legal framework.

The second ground, based on Padfield v Minister of Agriculture, Fisheries and Food, argued the guidance frustrated the purposes of the Police Reform and Social Responsibility Act 2011. The judge held that the Act conferred no relevant statutory discretion capable of being thwarted in the manner Padfield requires, and that the claimant's attempt to extend the principle beyond discretionary statutory powers was unsustainable, following the Court of Appeal's recent rejection of a similar argument in R (Refugee and Migrant Forum of Essex and London) v Secretary of State for the Home Department.

On Wednesbury unreasonableness, the judge acknowledged the claimant's reliance on cautionary reports from bodies including the Independent Office for Police Conduct, the National Police Chiefs' Council and the Information Commissioner, but found the Commissioner had engaged substantively with this material during the policy's development, including amending a data protection impact assessment in response to the Information Commissioner's concerns. The judge was not persuaded that a ninety day retention window was irrational when weighed against the alternatives of shorter periods or indefinite retention, noting the claimant had not explained why a different timeframe would have been required.

The fourth ground, alleging a violation of the right to a fair trial under Article 6 ECHR, was dismissed on the basis that any prejudice arising from deleted material in BB's specific prosecution was a matter for determination in the Crown Court, not the Administrative Court, particularly given the absence of the Crown Prosecution Service as a party and uncertainty over what material had or had not been disclosed.

The judgement noted with some concern that DC Archer had only identified two further exported WhatsApp chats after the hearing had already begun, but concluded this evidential complication did not undermine the lawfulness of the guidance itself. All four grounds were dismissed and the claim for judicial review failed.