Copthorne Holdings Ltd. v. The Queen, 2005 DTC 1133, 2005 TCC 491 -- summary under Solicitor-Client Privilege

Although communications among various law firms were privileged, documents exchanged between the taxpayer's Canadian solicitors and third party companies that were submitted to be under the same de facto control as the taxpayer were found not to be privileged as the taxpayer had failed to satisfy the Court that the companies were sufficiently intertwined as to warrant overriding the fact that they were separate corporate entities.