High Court upholds Met Police 90-day WhatsApp auto-deletion policy despite ICO concerns

Mr Justice McKendrick, handing down judgment on 31 July following a two-day hearing in May, rejected all four grounds advanced by the claimant, an anonymised defendant awaiting trial in the Crown Court whose case was investigated in part through WhatsApp exchanges between the officer in the case and the complainant.

The claimant argued that the guidance:

- authorises unlawful conduct by directing the deletion of material that may be relevant to criminal investigations, contrary to the principles in Gillick and R (A) v Secretary of State for the Home Department;
- frustrates the purposes of the Police Reform and Social Responsibility Act 2011;
- is Wednesbury unreasonable, given warnings from the National Police Chiefs' Council, the Independent Office for Police Conduct and the ICO; and
- unjustifiably interferes with the right to a fair trial under Article 6 ECHR and at common law.

The Criminal Procedure and Investigations Act 1996 code of practice requires investigators to record and retain material obtained in a criminal investigation which may be relevant to it. The Met's guidance, dated August 2023, prohibits the use of instant messaging for evidential material or material generated in the course of an investigation engaging CPIA obligations, and instructs officers who unexpectedly receive such material to export the chat and upload it to the force's evidential repository, Connect.

The judgment also records the ICO's engagement with the force's data protection impact assessment, in which the regulator asked how deletion requests, subject access requests and freedom of information requests received within the 90-day window would be handled, and recommended that internal guidance be explicit about the limits of acceptable use.

McKendrick J held that the guidance does not misstate the law. It is concerned with managing instant messaging rather than purporting to give a full account of CPIA obligations, and if followed properly it directs officers away from using WhatsApp for investigative material altogether.

The judge observed that the guidance's statement that unexpectedly received evidential chats "can" be exported should properly read "should", but was satisfied that officers reading the document as a whole would understand the necessity of preserving such material.

The unreasonableness challenge failed principally because the reports and advice relied upon by the claimant went to the decision to deploy WhatsApp on Met devices at all - a decision not under challenge - rather than to the 90-day deletion setting specifically.

The judgment records that the force's original plan envisaged lawful business monitoring producing a comprehensive, centrally searchable record of messages capable of supporting data protection and FOI rights, but that no such central database materialised before rollout.

The force's updated impact assessment stated that residual risks to the rights and freedoms of individuals had to be assumed to remain high.The judge nonetheless found the choice of a 90-day window over shorter periods or indefinite retention was a judgment for the Commissioner, and that the claimant had not shown no reasonable police commissioner could have adopted it.

The judgment however did record a number of reservations about the Metropolitan Police's guidance. The judge noted concern about the deletion of potentially relevant material in criminal proceedings where liberty is at stake, and twice described as concerning the evidence of the officer in the case, who discovered only after being directed to file a further witness statement in the judicial review that she had made two additional WhatsApp chat exports overlooked when she responded to the defence case statement in the Crown Court proceedings.

The Article 6 ground was dismissed as a matter for the criminal court, where the claimant remains free to cross-examine the officer and to argue abuse of process.

The claimant is anonymised by court order and his trial is due to start in November 2026.

The judgment in BB, R (on the application of) v The Commissioner of Police of the Metropolis [2026] EWHC 1986 (Admin) is available here: https://caselaw.nationalarchives.gov.uk/ewhc/admin/2026/1986