BB, R (on the application of) v The Commissioner of Police of the Metropolis

Under the objective policy-lawfulness approach, a public policy is unlawful if it directs conduct contrary to law, breaches an applicable duty to give accurate legal advice, or purports to give a complete but misleading account of the law. A policy need not be a legal textbook. The Criminal Procedure and Investigations Act 1996 does not itself impose the relevant retention duty directly on police forces, although its Code and disclosure guidance require investigators to record and retain potentially relevant material. A police messaging policy read as a whole may lawfully limit use, prohibit investigative and evidential material, and require unexpected material to be exported. A statutory-purpose challenge requires a statutory discretion. Rationality review retains a high threshold, and concrete fair-trial disclosure issues ordinarily belong in the criminal court.

The claimant sought judicial review of the defendant’s Guidance for instant messaging applications on MPS-issued devices. The challenge focused on the mandatory use of a 90-day disappearing-message function without a reliable central storage mechanism. The claimant argued that the Guidance authorised breaches of criminal-investigation recording and retention obligations, frustrated the statutory purposes of the Police Reform and Social Responsibility Act 2011, was unreasonable, and interfered with fair-trial rights under Article 6 ECHR.

Permission was granted on all four grounds. The court considered the Guidance, evidence concerning its design and monitoring, and further evidence about WhatsApp communications in the claimant’s criminal case. The central issues were whether the policy misstated the CPIA regime, exceeded the statutory framework, was irrational, or could be declared unlawful because of possible disclosure consequences in pending Crown Court proceedings.

1. Ground 1. Applying R (A) v Secretary of State for the Home Department [2021] UKSC 37, the court compared the law with the conduct objectively required by the Guidance. The statutory provisions relied on in the Police Reform and Social Responsibility Act 2011 created neither a duty to provide accurate legal advice nor a policy purporting to give a complete account of CPIA law. Ground 1 therefore failed.
2. CPIA obligations. Part 1 of the Criminal Procedure and Investigations Act 1996 concerned prosecutor obligations. Section 23 imposed a duty on the Secretary of State to prepare a Code, while the Code and Attorney General’s Guidelines supplied the relevant recording and retention requirements. Read as a whole, the Guidance prohibited use of WhatsApp for evidential or investigative material engaging CPIA obligations and directed officers to export material received unexpectedly. The reference to material being capable of export should properly be read as requiring export. The Guidance did not misstate the law.
3. Ground 2. Applying Padfield v Minister of Agriculture, Fisheries and Food [1968] AC 997 and following R (Refugee and Migrant Forum of Essex and London and another) v Secretary of State for the Home Department (No. 1) [2025] EWCA Civ 1843, the court held that a Padfield challenge requires a statutory discretion. The PRSRA conferred no such discretion to issue this Guidance. Ground 2 was dismissed.
4. Ground 3. The challenge concerned the 90-day deletion and storage arrangement, not the deployment of WhatsApp generally. The decision-maker had considered relevant reports, stakeholder views, risks and alternatives. The 90-day period represented a rational balance between preserving material and avoiding indefinite retention. The high Wednesbury threshold was not met. Ground 3 was dismissed.
5. Ground 4. The principle in Natunen v Finland (2009) 49 E.H.R.R. 32 was factually remote. Any concrete question about relevance, disclosure or unfairness in the claimant’s criminal case had to be assessed holistically by the Crown Court, where cross-examination and abuse-of-process applications were available. The Administrative Court should not grant the declaration sought on the incomplete record before it.

All four grounds failed and the claim for judicial review was dismissed.

Permission for judicial review on all four grounds was granted by order dated 4 November 2025. The judgment records no appeal.