A. AND OTHERS v. THE UNITED KINGDOM JUDGMENT 43 advocates will be able to take from the client before they see the closed material. Both judge and special advocates will have to probe the claim that the closed material should remain closed with great care and considerable scepticism. There is ample evidence from elsewhere of a tendency to over-claim the need for secrecy in terrorism cases: see Serrin Turner and Stephen J Schulhofer, The Secrecy Problem in Terrorism Trials, 2005, Brennan Centre for Justice at NYU School of Law. Both judge and special advocates will have stringently to test the material which remains closed. All must be alive to the possibility that material could be redacted or gisted in such a way as to enable the special advocates to seek the client’s instructions upon it. All must be alive to the possibility that the special advocates be given leave to ask specific and carefully tailored questions of the client. Although not expressly provided for in CPR r 76.24, the special advocate should be able to call or have called witnesses to rebut the closed material. The nature of the case may be such that the client does not need to know all the details of the evidence in order to make an effective challenge. 67. The best judge of whether the proceedings have afforded a sufficient and substantial measure of procedural protection is likely to be the judge who conducted the hearing. ...” Lord Carswell observed: “There is a very wide spectrum of cases in which closed material is relied on by the Secretary of State. At one extreme there may be cases in which the sole evidence adverse to the controlee is closed material, he cannot be told what the evidence is or even given its gist and the special advocate is not in a position to take sufficient instructions to mount an effective challenge to the adverse allegations. At the other end there may be cases where the probative effect of the closed material is very slight or merely corroborative of strong open material and there is no obstacle to presenting a defence. There is an infinite variety of possible cases in between. The balance between the open material and the closed material and the probative nature of each will vary from case to case. The special advocate may be able to discern with sufficient clarity how to deal with the closed material without obtaining direct instructions from the controlee. These are matters for the judge to weigh up and assess in the process of determining whether the controlee has had a fair trial. The assessment is ... fact-specific. The judge who has seen both the open and the closed material and had the benefit of the contribution of the special advocate is in much the best position to make it. I do consider, however, that there is a fairly heavy burden on the controlee to establish that there has been a breach of Article 6, for the legitimate public interest in withholding material on valid security grounds should be given due weight. The courts should not be too ready to hold that a disadvantage suffered by the controlee through the withholding of material constitutes a breach of Article 6.” Lord Brown held as follows: “There may perhaps be cases, wholly exceptional though they are likely to be, where, despite the best efforts of all concerned by way of redaction, anonymisation, and gisting, it will simply be impossible to indicate sufficient of the Secretary of State’s case to enable the suspect to advance any effective challenge to it. Unless in these cases the judge can nevertheless feel quite sure that in any event no possible challenge could conceivably have succeeded (a difficult but not, I think, impossible conclusion to arrive at ...), he would have to conclude that the making or, as the case may be, confirmation of an order would indeed involve significant injustice to the suspect. In short, the suspect in such a case would not have been accorded even ‘a substantial measure of procedural justice’ (Chahal, [cited above] § 131)