Legitimate forensic purpose
24 It may be accepted, that documents that are relevant to the credit of a witness may be capable of providing a legitimate basis for cross-examination. The respondents referred to and relied on Brand v Digi-Tech, where Hunter J observed at [36]:
...it is indisputable that, if the subpoenaed documents are by their description, arguably relevant or capable of providing a legitimate basis for cross-examination on credit matters, then an application to set aside a subpoena on the grounds of irrelevance of the documents to the proceedings is misconceived.
And see Fried v National Australia Bank Ltd [2000] FCA 911; (2000) 175 ALR 194 (Fried) at [24]; and Liristis v Gadelrabb [2009] NSWSC 441 at [4]; Carter v Hayes SM (1994) 61 SASR 451 at 453. Although, as Weinberg J observed in Fried at [28], s 102 of the Evidence Act 1995 (Cth) makes it plain that, subject to specific exceptions, evidence that is relevant only to a witness' credibility is inadmissible, and so some caution may need to be exercised when considering that as a basis for a subpoena.
25 Person 35 relied on Roberts-Smith (No 6) at [74], where Colvin J observed:
…In reaching that conclusion I note that to the extent that there may be documents that do not contain information about the subject matter of the Inquiry they would not be materially relevant to the defamation proceedings. Therefore, if and to the extent that it might be said that the content of some documents is sufficiently innocuous that there is no public interest in preserving the non-disclosure of their content, then that set of documents would be irrelevant in any event and therefore not discoverable and documents for which there would be no legitimate forensic purpose in seeking their production.
26 This observation was made in relation to the determination of a discovery dispute between the parties. Person 35 contended that the document is rendered innocuous, and as such is irrelevant to the proceedings.
27 "Innocuous" tends to suggest a document which is not harmful or injurious, as might be expected in relation to discovery.
28 Person 35 made what appears to be conflicting submissions on this aspect. On the one hand he contended that the document did not relate to anything to do with defamation proceedings, and was therefore irrelevant. That submission is only an assertion from the bar table, but accepting that is so for the purposes of argument, importantly, as a general proposition, a person's credit may be affected by matters personal to them and unrelated to the underlying proceedings. So much should be uncontroversial. Rather, it is a question of fact in the particular case whether such a matter affects a person's credit in respect to the evidence given by them. On the other hand, Person 35 submitted that the document itself, even in the redacted form, is prejudicial. Although that submission was made and included that knowledge of the existence of the document is itself prejudicial, curiously, Person 35's written submissions identify the nature of the document. That does not sit comfortably with Person 35's submission that the document does not contain adverse information. I do not agree with Person 35's characterisation of the document as "innocuous".
29 The very nature of the document, even in its redacted form, makes it arguably relevant to credit. Person 35's submission that the ADF has not yet made any decision in relation to the Document, does not detract from that. Person 35's submission that the release of the Document would result in an unnecessary sideshow in the defamation proceedings is dependent on the use to be made of it at trial and, as noted above, is properly a matter for the trial judge. Person 35's submission that the Document would be prone to misuse, does not address whether it has a legitimate forensic purpose. The use to be made of the Document will be a matter for the respondents, in accordance with the rulings of the trial judge. If it is used, what weight will be attached to what ensues from its use will be a matter for the trial judge in all the circumstances of the case. There is no basis to suppose that the trial judge would consider the document otherwise than appropriately. If counsel for Person 35 sought to put submissions to the trial judge as to the Document, including as to its protection, there is no reason to suppose he would be unable to do so. The respondents have established that there is a legitimate forensic purpose in the Document.