The Claimant applied for an order quashing a search warrant obtained by police under the Misuse of Drugs Act 1971. He was granted permission to apply for judicial review to challenge the warrant on two grounds:
- That the warrant had been issued on the basis of a deliberately false and exaggerated account of the execution of a previous warrant.
- There were material non-disclosures by police about that search and subsequent occasions on which police had entered the Claimant's home but found nothing.
The Chief Constable successfully claimed PII in respect of the majority of the contents of the warrant application, which had been provided to the Claimant in redacted form. Hon. Mr Justice Chamberlain heard submissions on the PII claim on 14 August 2020, and his Judgment is detailed below. The later case of R (Haralambous) v St Albans Crown Court  however confirmed that on an application for judicial review challenging a search warrant granted on the basis of material which was not and cannot be disclosed to the Claimant, the High Court can hold a CMP, despite the absence of express statutory authority to do so. This enables the High Court to consider all the material before the magistrate and to rely on that material in reaching its substantive decision without disclosing it to the Claimant.
The effect of a successful PII claim is generally that the material to which it relates becomes inadmissible for all purposes, neither the Court nor the parties can rely upon it. This differs fundamentally from a Closed Material Procedure (CMP), where material can be relied upon by the Court, but not disclosed to the parties, Al-Rawi v Security Service  UKSC 34 followed.
When considering whether to uphold the PII argument, the Court applied R. v Chief Constable of the West Midlands Ex p. Wiley  1 A.C. 274, which focussed on three issues:
- whether the evidence in relation to which PII was asserted was relevant to an issue in the proceedings;
- whether the disclosure of that evidence would harm the public interest; and, if so,
- whether an order for disclosure should be made, balancing that harm against the public interest in the administration of justice.
In Competition and Markets Authority v Concordia International Rx (UK) Ltd  EWHC 3448 (Ch), Marcus Smith J noted that the availability of a CMP affected the balance to be performed at the third stage, so that the arguments made by the party asserting PII had to be stronger in a case where the PII material was simply being withheld.
Application of Legal Principles
The application for the warrant contained summaries of intelligence reports on which the Chief Constable relied to seek the grant of the warrant. On the Wiley approach detailed above and when determining relevance, it was deemed necessary to consider all the information given to the magistrate in order to evaluate whether it was misleading to omit details of the earlier visits to the Claimant's home. Having considered those reports and hearing submissions from the Defendant's counsel, with the exception of one report, it was determined that the disclosure of any of the information contained in the redacted reports would damage the public interest in ways which justified the assertion of PII.
The risk of damage to the public interest that would be occasioned by disclosure would be substantial and the damage itself would be serious if the risk eventuated. The consequence of non-disclosure, on the other hand, was that the material covered by PII would be considered by the court in a CMP, an unfair procedural process to the Claimant. Overall, the damage caused by disclosure outweighed the damage to the public interest in the administration of justice that would arise from non-disclosure. The claim for PII was therefore upheld.
Procedure and Conduct to be followed for a Substantive Hearing
Hon. Mr Justice Chamberlain set out the following procedure:
(1) Where the Court grants permission to apply for judicial review in a challenge to a warrant, and the Chief Constable has claimed PII over relevant material, the Court should also give directions for a hearing to determine the PII claim and a substantive hearing to determine the judicial review claim, preferably before the same Judge.
(2) If the PII claim is upheld at the first hearing, the Court should give directions dealing with (i) the time for disclosure of and response to any new material; (ii) whether the case was sufficiently exceptional that a special advocate should be appointed to represent the Claimant in the CMP; and (iii) the listing of the substantive hearing.
(3) At the substantive hearing, an open hearing should take place first, followed by a closed hearing. The Claimant's representatives should be available for a short further open hearing. Counsel for the public authority has a special obligation to assist the Court by identifying any points arising from the closed material which might arguably support the Claimant or undermine the defence.
(4) After the substantive hearing, open and closed judgments should be prepared. Care should be taken to identify in the open judgment every conclusion that has been reached in whole or in part on the basis of evidence referred to in the closed judgment, Bank Mellat v HM Treasury  UKSC 38 followed.
This is a very helpful and clear judgment that confirms the procedure to be followed in regards to the conduct of judicial review hearings involving a challenge to a search warrant and PII arguments. Further, Hon. Mr Justice Chamberlain clearly demonstrates the approach to be taken when assessing PII arguments in this context.