(dissenting). In my view, the majority has effectively submerged the key issue here: whether the trial judge made a proper initial determination, required by Commonwealth *404v. Bishop, 416 Mass. 169, 179-183 (1993), whether the Massachusetts Society for the Prevention of Cruelty to Children (MSPCC) and the Department of Social Services (DSS) counseling records were, in fact, privileged. Moreover, the majority says little or nothing about the heretofore vaguely defined standards relevant to making such a determination. These issues are crucial to assessing the defendant’s claims. However, on the record before us, there are simply too many unanswered questions to permit meaningful review of these points. The only prudent course, therefore, would be to remand the case to the Superior Court for a further hearing on the defendant’s motion for production of the contested counseling records.
The majority, however, rejects the necessity for even this brief detour. Given the extraordinary power of Bishop and its cognate cases to deprive a defendant of a cornerstone constitutional right — the right to marshal all relevant evidence in his defense — special care must be taken to ensure that all procedural safeguards mandated by these decisions are strictly enforced. Here there were irregularities, as the majority concedes. Due process requires correction of these missteps before the defendant’s rights are set aside. For this reason, I respectfully dissent. I set out my analysis at some length, since this issue likely will recur in future cases.
1. Adequacy of privilege determination. At the time the defendant’s motion for production of the complainants’ counseling records was considered, the standard for determining whether these particular forms of potentially privileged documents were susceptible to discovery was provided exclusively by Commonwealth v. Bishop, supra. That is to say, the additional burdens imposed on a defendant seeking access to privileged records imposed by Commonwealth v. Fuller, 423 Mass. 216, 226 (1996), had not yet been made applicable to materials other than those described in G. L. c. 233, § 20J.1 As the Commonwealth concedes, and as the majority concludes, *405the DSS and MSPCC records sought here are not rape counselor records as defined by that section. Rather, the parties stipulated at trial, and agree on appeal, that the records were subject only to the social worker privilege as expressed in G. L. c. 112, §§ 135A and 135B. See Commonwealth v. Sheehan, 435 Mass. 183, 185 & n.1 (2001) (applying Bishop to cases tried before Fuller principles were deemed to control proceedings).
Under Bishop, the motion judge was required first to assess whether the documents sought were subject to any privilege and, if so, to determine whether the privilege had been waived. As noted already by the majority, the judge wrote:
“The defendant here is accused of molesting his own children and asks this court to order production of DSS and counselling records generated since the children ‘disclosed’ the alleged abuse. Certain of the children’s confidential psychiatric records have already been provided to defense counsel including the medical records prepared by the psychiatrist to whom the children originally made their disclosures. This prior disclosure of records suggests that concerns as to the confidentiality of the records requested have less urgency than the confidentiality concerns raised in [Commonwealth] v. Fuller, 423 Mass. 216 [(1996)]. Moreover, confidentiality was almost certainly not a motivating factor behind any participation in therapy by the children at issue. Nevertheless, this Court feels compelled to deny the defendant’s motion based on the precepts articulated in [Commonwealth] v. Bishop, 416 Mass. 169 [(1993)] .... In short, the motion is denied based on an insufficien[cy] of relevance.”
Unfortunately, the motion judge’s order confuses and conflates the initial analytical steps mandated by Bishop. Specifically, she failed to comply with Bishop’s basic procedural mandate that a motion judge, having found the existence of a privilege, must provide detailed written findings explaining the specific type, nature, and basis of the applicable privilege. See Commonwealth v. Bishop, 416 Mass. at 181. Merely reciting the *406existence of a privilege, without more, is an insufficient basis, as matter of law, for denying a motion for production of confidential records. See Commonwealth v. Pare, 427 Mass. 427, 429-430 (1998). The motion judge’s findings were simply not sufficiently detailed to meet the Bishop standard.
As a result of this procedural shortcoming, we cannot be sure how (or whether) the judge dealt with the evidence suggesting that any privilege with respect to the children’s counseling records had been waived. As conceded by the majority, and as observed by the motion judge, the defendant received copies of the counseling records of Fred Moder, the clinical social worker to whom both children made the initial reports of abuse. These materials contained significant information, both about the nature of the abuse allegedly suffered by the children, as well as the children’s reactions to same.
While adverting obliquely to the possible effects of these disclosures on the status of the children’s privilege (“[tjhis prior disclosure of records suggests that concerns as to the confidentiality of the records requested have less urgency than the confidentiality concerns raised in [Commonwealth] v. Fuller, 423 Mass. 216 [(1993)]”), the judge makes no definitive findings of fact or rulings of law on the issue. Rather, the motion judge’s order suggests she may have believed that it was unnecessary to reach the privilege question because, in her view, the defendant had failed to satisfy the relevance requirements of Bishop.
The majority takes note of the serious procedural defects in the motion judge’s handling of the privilege determination, concluding that “[t]he motion judge’s written decision combined the privilege determination stage with the relevancy determination stage” (emphasis supplied). Ante at note 9. However, the majority then condones this fatal failure to abide by the plain mandate of Bishop by speculating that the judge may merely have been wrestling with the question of whether Bishop afforded the correct standard for review, or whether the elevated standard in Fuller, as discussed above, applied. The basis for this speculation is elusive to say the least. In any event, and much more important, neither Fuller, nor any case postdating Bishop, relieves a motion judge of his duty to consider *407separately, as a threshold matter, whether counseling documents subject to a production request are privileged. The bottom line is that, regardless of the reason, the judge failed to follow required procedures; due process entitles the defendant to more.
By passing over the question of privilege because, in her view, the defendant would be unable to prove relevancy, the motion judge may have missed the dispositive issue here. At common law, the voluntary disclosure of privileged material constitutes a waiver of the privilege. This principle is echoed in rule 510 of the Proposed Massachusetts Rules of Evidence, which provides that “[a] person upon whom these rules confer a privilege against disclosure waives the privilege, if he . . . voluntarily discloses or consents to disclosure of any significant part of the privileged matter.” This concept is most commonly applied in the criminal law context in connection with the various testimonial privileges, see, e.g., Commonwealth v. Goldman, 395 Mass. 495, 499-500 (1985), but applies with equal force to the release of confidential records. See Commonwealth v. Clancy, 402 Mass. 664, 667 (1988). See also Commonwealth v. Clemons, 12 Mass. App. Ct. 580, 584 n.2 (1981).
Needless to say, the mere fact that some privileged documents have been disclosed does not automatically destroy the privileged status of cognate materials — here the DSS and MSPCC reports. However, there is a serious question in this case — and one not adequately addressed by the motion judge in her order — whether the release of Moder’s records amounted to a voluntary waiver of privilege with respect to all counseling records connected with the charged assault. As noted already, this question of whether a privilege attaches to the documents sought by the defendant is a crucial threshold issue on which the applicability of the entire Bishop regime hinges. All ambiguities on this point, therefore, need to be erased before we can begin to determine whether Bishop was correctly applied in this instance.
To justify the motion judge’s actions, the majority relies on the dichotomy between concepts of privileged “subject matter” and privileged “communications.” In essence, the majority takes the position that even if the victims here voluntarily consented, through their guardian, to the release of Moder’s *408counseling records, and even if the information in these materials were identical to the material contained in the DSS and MSPCC reports, nonetheless there would be no waiver. In the majority’s view, each separate communication of confidential material carries with it a discrete privilege that must be individually waived. Thus, in the majority’s view, if a sexual assault victim relates precisely the same information to three doctors, each of whom produces a separate record of the conversation, the voluntary disclosure of two of the reports would not constitute a waiver of confidentiality with respect to the third.
As a basis for this view, the majority relies on two cases, Commonwealth v. Clancy, 402 Mass. at 669, and Commonwealth v. Goldman, 395 Mass. at 500, neither of which, in fact, supports the majority’s approach. Both Clancy and Goldman stand for the well-settled principle that “a witness does not relinquish [a privilege in a confidential record] ... by merely testifying to events falling within the subject matter of a privilege.” Commonwealth v. Clancy, 402 Mass. at 669. As the Supreme Judicial Court stated in Goldman, 395 Mass. at 499-500:
“[there are] two distinct scenarios. In the first, a witness testifies as to events which happen to have been a topic of a privileged communication. In the second, the witness testifies as to the specific content of an identified privileged communication.”
Privilege is not waived in the first situation, the court concluded, but it is in the second. See Goldman, supra at 500. Neither case, however, has anything to say about whether expressly waiving a privilege with respect to a confidential communication also waives any privilege inhering in the same communication made to a different confidante.
■ Contrary to the majority’s view, the general rule in Massachusetts, as elsewhere, is that once a communication is conveyed to a third party, any privilege in the communication is destroyed. See Liacos, Brodin, & Avery, Massachusetts Evidence § 13.4.5 (7th ed. 1999); Drew v. Drew, 250 Mass. 41, 44-45 (1924). See also Commonwealth v. Michel, 367 Mass. 454, 460-461 (1975). The policy basis for such an approach is *409plain: confidentiality rules are designed to promote full discussion of private, possibly embarrassing information with confidential counselors by assuring that the substance of the communication will remain private. See Commonwealth v. Bishop 416 Mass. at 176. See also Commonwealth v. Collett, 387 Mass. 424, 428 (1982).
Once the details of a confidential communication have been publicly disclosed, no policy interest is served by continuing to protect that communication with a privilege, at least where disclosure was consensual on the part of the privilege holder. This is equally true whether the communication was made to one or more confidantes. Once the communication is made public, the basis for the privilege disappears with respect to all recipients of that communication. This view is entirely consistent with rule 510 of the Proposed Massachusetts Rules of Evidence which, as noted, provides that a privilege dissipates if the privilege holder “voluntarily discloses or consents to disclosure of any significant part of the privileged matter.” See also Proposed Mass.R.Evid. 503(a)(3) (communications confidential if not intended to be conveyed to others).
As we stated in Commonwealth v. Pare, 43 Mass. App. Ct. 566, 571 (1997), S.C., 427 Mass. 427 (1998): “The Bishop protocols have not altered the traditional recognition that testimonial privileges, which have the effect of inhibiting full disclosure of the truth, are exceptional and to be strictly construed.” We added in Pare, quoting Bishop itself, that to assure a defendant’s constitutional right to a fair trial, any doubts as to the applicability of a privilege must be resolved “in favor of disclosure.” Ibid., quoting from Commonwealth v. Bishop, 416 Mass. at 177. The majority’s expansive concept of privilege directly opposes these concepts. If the DSS and MSPCC records here are substantially cumulative of Moder’s reports, due process requires that they all be disclosed.
2. Standard for finding waiver of privilege. To the extent the question of waiver of privilege is largely a fact issue that must be assessed on a case-by-case basis, I believe, as noted already, that the only option here is to remand the matter to the motion judge for a further hearing. The subject matter of such a hearing would be two-fold: first, the motion judge would consider whether it appears from the record before her, supplemented by *410any additional materials the parties may wish to adduce, that Moder’s records and reports constitute a “significant” (quoting proposed rule 510) portion of the otherwise privileged counseling materials in this case. To this end, the motion judge must assess whether the documents already disclosed are similar in character, scope and form to the documents still sought by the defendant, or whether they merely constitute a small and insignificant subset of the main body of privileged materials, with but little overlap and slight affinity.
If the judge were to find that a significant part (as defined above) of the corpus of otherwise privileged materials here has been disclosed, she should then consider a second, separate issue: whether the disclosure was knowing and voluntary vis-a-vis the two child victims, in whom the privilege resides. See Commonwealth v. Neumyer, 432 Mass. 23, 35 n.15 (2000). Where a child is too young or otherwise is unable to engage in meaningful consultation about the merits of waiving a privilege, it is permissible for a court to permit a parent to waive (or refuse to waive) the privilege on the child’s behalf. If, as it appears, the victims’ mother voluntarily consented to the release of the privileged documents surrendered to the defendant — a point that must be verified at the hearing — her action likely can be imputed to the children.2
However, where the interests of child and parent diverge, a court is required to appoint a guardian to safeguard the child’s interests in maintaining the confidentiality of privileged records. See Adoption of Diane, 400 Mass. 196, 202 (1987). Cf. G. L. c. 233, § 20B (regarding appointment of guardians for the purpose of asserting a patient’s privilege). Although there is nothing in the record here supporting such an inference, if it emerges at the hearing that there is good reason to believe that the victims’ mother was motivated by concerns at odds with the *411best interests of the children when she agreed to release Moder’s records and reports, then the motion judge cannot find any waiver in the disclosure of those materials. Again, the privilege belongs to the children; only they, or those properly authorized to act on their behalf, can waive the privilege.
If the motion judge were to determine there has been a waiver of the privilege, the defendant would be entitled to examine all of the materials sought in his original discovery order. Based upon that review, the defendant could then file a motion for a new trial, setting out precisely how the newly disclosed materials might have advanced his defense. A new trial would be required here only if an improper failure to disclose the requested materials resulted in actual prejudice. Absent prejudice, no relief would be required.
Commonwealth v. Oliveira, 431 Mass. 609, 617 (2000), might be read to suggest that Commonwealth v. Fuller, 423 Mass. 216, 226 (1996), was intended to encompass a broader range of privileged documents than those defined by G. L. c. 233, § 20J. However, a close reading of Fuller reveals no such express intention. Indeed, the decision, while allowing that Bishop applies to all forms of privileged material, discusses at length why § 20J docu-*405merits, as opposed to other types of privileged material, should be subject to a stricter rule. In any event, the motion judge applied a pure Bishop test here and, since the defendant’s motion was decided before the decision in Oliveira, I would likewise apply the Bishop rule, unreformed by Fuller.
The majority speculates, without any basis in the record, that the mother might not have been “aware of the privilege” protecting the confidentiality of the children’s treatment records. Needless to say, any waiver of the privilege here must have been voluntary and knowing to be effective. However, it is not an appellate court’s function to speculate about such important fact issues. It is precisely because we know so little from the record about the circumstances attending the release of Moder’s reports that the case, in my view, must be remanded for a further hearing.