"The attorney-client privilege, set forth at Evidence Code section 954, confers a privilege on the client 'to refuse to disclose, and to prevent another from disclosing, a confidential communication between client and lawyer . . . .' The privilege 'has been a hallmark of Anglo-American jurisprudence for almost 400 years.' (Mitchell v. Superior Court (1984) 37 Cal.3d 591, 599.) Its fundamental purpose 'is to safeguard the confidential relationship between clients and their attorneys so as to promote full and open discussion of the facts and tactics surrounding individual legal matters. . . .Although exercise of the privilege may occasionally result in the suppression of relevant evidence, the Legislature of this state has determined that these concerns are outweighed by the importance of preserving confidentiality in the attorney-client relationship. As this court has stated: "The privilege is given on grounds of public policy in the belief that the benefits derived therefrom justify the risk that unjust decisions may sometimes result from the suppression of relevant evidence." ' (Id. at pp. 599-600.) 'The privilege is absolute and disclosure may not be ordered, without regard to relevance, necessity or any particular circumstances peculiar to the case.' " (Costco Wholesale Corp. v. Superior Court (2009) 47 Cal.4th 725, 732.)