The whole purpose of Cabinet privilege, where it is applied correctly, is to prevent disclosure especially in cases like this. I suppose the key is, was privilege applied correctly. In that regard, on motion a court can order a review of the description of documents and evidence withheld, but YMMV.
Public Prosecution Service Desktop:
"Section 39 of the CEA acts as an absolute bar to the disclosure of Cabinet Confidences as defined in s. 39(2). Whereas a judge assesses and makes the determination regarding disclosure or protection of information under ss. 37 and 38 of the CEA, the determination of Cabinet Confidences under s. 39 is made by the Clerk of the Privy Council or a Cabinet Minister. Where a certificate is filed under s. 39 certifying that the information constitutes a Cabinet Confidence, a court must refuse disclosure of that information without examination or hearing of the information.Objections under s. 39 must be made in writing, certifying that the information constitutes a Cabinet Confidence."
"The consultation process described above also applies where an accused seeks disclosure of information which has been certified as a Cabinet Confidence. The Clerk’s Certificate produced in court simply describes the protected documents without revealing their contents. This Certificate is evidence that the listed documents are protected from disclosure. A court may not review the Cabinet documents listed in the Certificate. Although the court is not entitled to go behind a proper certificate filed under s. 39, the court can review the certificate to determine if, on its face, it complies with this section."
