4 A party's waiver of privilege may be implied by operation of law, even though it does not represent the subjective intention of the party; Benecke v National Australia Bank (1993) 35 NSWLR 110 and Mann v Carnell [1999] HCA 66; (1999) 168 ALR 86, par29. A party may waive privilege in relation to material by disclosing it in a manner that is inconsistent with the confidentiality which the privilege serves to protect. Depending upon the circumstances of the case, considerations of fairness may be relevant to a determination of whether conduct demonstrates such an inconsistency; Mann v Carnell (supra) at pars29 and 34. The law is not that every voluntary disclosure of privileged material to a third party necessarily waives privilege; Mann v Carnell (supra) at par30. In the course of preparing a matter for trial, it is common for parties to provide privileged documents to other parties with a common interest and to potential witnesses. Without more I am unable to conceive how, in the ordinary course, conduct such as this would be inconsistent with the preservation of the confidentiality of the material. The requisite inconsistency may be manifested when a party indicates an intention to rely upon evidence of a witness which is based upon privileged material provided to that witness. This, not infrequently, occurs when a party delivers an affidavit or proof of expert evidence of a witness. In that situation, the inconsistency between the party's conduct and the maintenance of a claim for privilege in relation to the material relied upon by the witness is compounded by the unfairness of allowing the party's witness to refer to that material whilst also allowing that party to shield the material from scrutinisation and testing by a claim of privilege. Jessup & Anor v Gorjup 139/1997 is a case where a claim for privilege was lost in these circumstances.