Challenge to the Metropolitan Police Service Guidance on the Use of Instant Messaging Apps (including Whatsapp) Dismissed

Saara Idelbi, leading Ellie Mullett, appeared for the Commissioner of Police of the Metropolis in a challenge to force guidance on the use of disappearing messages on issued devices.

In R (BB) v Commissioner of Police of the Metropolis [2026] EWHC 1986 (Admin), McKendrick J dismissed all four grounds of challenge to the MPS’s guidance on the use of instant messaging apps (including WhatsApp) on force devices, and in particular to the direction that the disappearing chat function be enabled at ninety days.

The court concluded that the guidance did not authorise unlawful conduct. The guidance did not misstate the police’s obligations under the Criminal Procedure and Investigations Act 1996 (CPIA). WhatsApp was not to be used for material that ought to be retained under the CPIA, and included instructions to export and retain material where such was unexpectedly received.

Additionally, the court found that the Commissioner had carefully considered stakeholder advice, including from the Information Commissioner and the IOPC, and that a ninety-day retention period struck a reasonable balance against the risks that might arise from indefinite retention.

For public authorities the practical point lies in the retention mechanism rather than the deletion setting. A policy which makes clear what needs to be retained and sets out how to retain such may be lawful even if an automated deletion setting is enabled.

39 Essex Chambers’ barristers Saara Idelbi and Ellie Mullett were instructed by the Directorate of Legal Services, Metropolitan Police Service.

The full judgment can be found: here