“As to the process that must be followed when considering whether material is protected by PII: (1) The general rule is that the court should consider first representations by the party asserting PII (in this case, the CMA), then by the party the subject of the warrant (Concordia) in ‘open’ proceedings, then further representations by the party asserting PII in the subject's absence in ‘closed’ proceedings:Commissioner of Police for the Metropolis v Bangs[2014] EWHC 546 (Admin) (‘Bangs’) at [31]. (2) So far as possible, purely legal matters should be resolved in the ‘open’ proceedings:Bangsat [32]. (3) Where it is necessary to hold ‘open’ and ‘closed’ hearings, the judge must give ‘open’ and ‘closed’ judgments. It is highly desirable, in the ‘open’ judgment, to identify every conclusion in that judgment which has been reached in whole or in part in the light of points made in evidence referred to in the ‘closed’ judgment and state that this is what has been done:Bank Mellat v HM Treasury (No 2)[2013] UKSC 38 at [68].” [68].”
“27. But it must be noted that the adverse effect on the public interest in the administration of justice is materially greater under the present dispensation than previously. Previously, the worst that could happen was that relevant material was withheld generally. Now, the position is that relevant material is deployed before the court in the absence of an interested party. Inevitably, the court loses the benefit of the scrutiny and submissions of that interested party. (Fn: This sort of scrutiny is very important in reaching properly founded decisions. See, for example, the research described in Haidt, The Righteous Mind, 1st ed. (2012) at 75-76.) 28. It follows that the adverse effect on the due administration of justice is significantly greater in a case where PII material is being deployed without sight to one party than where it is simply being withheld from everyone. That is because one party (here, the CMA) can refer to and deploy in argument material that is unavailable to the other party to the dispute (here, Concordia). 29. That must mean that the cogency of the PII arguments made by the party asserting PII must be stronger than in a case where the PII material is simply being withheld. In short, the balancing exercise in a case such as this is different to the balancing exercise contemplated in previous cases in that there is this additional factor to take into account.”