What is the legal test for disqualifying a solicitor for failing to disclose privileged information?

9 Both sides rely upon the test for disqualification set out in MacDonald Estate v. Martin (1991), 1990 CanLII 32 (SCC), 77 D.L.R. (4th) 249 (S.C.C.) per Sopinka J. for the majority at p.267: "... the test must be such that the public represented by the reasonably informed person would be satisfied that no use of confidential information would occur. That, in my opinion, is the overriding policy that applies and must inform the court in answering the question: Is there a disqualifying conflict of interest? In this regard, it must be stressed that this conclusion is predicated on the fact that the client does not consent to but is objecting to the retainer which gives rise to the alleged conflict. Typically, these cases require two questions to be answered: (1) Did the lawyer receive confidential information attributable to a solicitor-and-client relationship relevant to the matter at hand? (2) Is there a risk that it will be used to the prejudice of the client?" and further at p.264: "... In my opinion, once it is shown by the client that there existed a previous relationship which is sufficiently related to the retainer from which it is sought to remove the solicitor, the court should infer that confidential information was imparted unless the solicitor satisfies the court that no information was imparted which could be relevant. This will be a difficult burden to discharge. Not only must the court's degree of satisfaction be such that it would withstand the scrutiny of the reasonably informed member of the public that no such information passed, but the burden must be discharged without revealing the specifics of the privileged communication. Nonetheless, I am of the opinion that the door should not be shut completely on a solicitor who wishes to discharge this heavy burden."