"[31] In Giannarelli, Mason CJ said that "the barrister's immunity, if it is to be sustained, must rest on considerations of public policy". His Honour explained that the term "immunity" was used in a sense which assumed that rights and duties might otherwise exist at common law, but the immunity is sustained on considerations of public policy and "the injury to the public interest that would arise in the absence of immunity". Of the various factors advanced to justify the immunity, "the adverse consequences for the administration of justice which would flow from the re-litigation in collateral proceedings for negligence of issues determined in the principal proceedings" (emphasis added) was held to be determinative. The significance of the reference to the administration of justice is of fundamental importance to the proper understanding of the immunity and its foundation.
[32] To adopt the language found in the cases considering Ch III of the Constitution, the central concern of the exercise of judicial power is the quelling of controversies. Judicial power is exercised as an element of the government of society and its aims are wider than, and more important than, the concerns of the particular parties to the controversy in question, be they private persons, corporations, polities, or the community as personified in the Crown or represented by a Director of Public Prosecutions. No doubt the immediate parties to a controversy are very interested in the way in which it is resolved. But the community at large has a vital interest in the final quelling of that controversy. And that is why reference to the "judicial branch of government" is more than a mere collocation of words designed to instil respect for the judiciary. It reflects a fundamental observation about the way in which this society is governed. …
[34] A central and pervading tenet of the judicial system is that controversies, once resolved, are not to be reopened except in a few, narrowly defined, circumstances. That tenet finds reflection in the restriction upon the reopening of final orders after entry and in the rules concerning the bringing of an action to set aside a final judgment on the ground that it was procured by fraud. The tenet also finds reflection in the doctrines of res judicata and issue estoppel. Those doctrines prevent a party to a proceeding raising, in a new proceeding against a party to the original proceeding, a cause of action or issue that was finally decided in the original proceeding. It is a tenet that underpins the extension of principles of preclusion to some circumstances where the issues raised in the later proceeding could have been raised in an earlier proceeding
[35] The principal qualification to the general principle that controversies, once quelled, may not be reopened is provided by the appellate system. But even there, the importance of finality pervades the law. Restraints on the nature and availability of appeals, rules about what points may be taken on appeal and rules about when further evidence may be called in an appeal (in particular, the so-called "fresh evidence rule") are all rules based on the need for finality. As was said in the joint reasons in Coulton v Holcombe. "[i]t is fundamental to the due administration of justice that the substantial issues between the parties are ordinarily settled at the trial". …
[37] Parties who fail in litigation, whatever its subject, may well consider the result of that litigation to be wrong, even unjust. Seldom will a party have contested litigation without believing, or at least hoping, that it will be resolved in that party's favour. If that party does not succeed, an explanation for failure may be sought in what are perceived to be the failures of others - the judge, the witnesses, advocates - anyone other than the party whose case has been rejected. …
[39] From as early as the 16th century, a disappointed litigant could not sue those who had given evidence in the case. That is, the disappointed litigant could not seek to demonstrate that witnesses had given, or parties had suborned, perjured evidence or that witnesses or parties had conspired together to injure that litigant. Nor could the disappointed litigant seek to demonstrate that what was said by the witnesses had defamed that litigant. All such actions were precluded or answered by an absolute privilege. It mattered not how the action was framed. And it mattered not whether the disappointed litigant alleged that the witness had acted deliberately or maliciously. No action lay, or now lies, against a witness for what is said or done in court. It does not matter whether what is done is alleged to have been done negligently or even done deliberately and maliciously with the intention that it harm the person who would complain of it. The witness is immune from suit and the immunity extends to preparatory steps. That the immunity must be pleaded as a defence makes it nonetheless an immunity from suit. As the whole Court said in Lange v Australian Broadcasting Corporation.
"The result [of the defence] is to confer upon defendants, who choose to plead and establish an appropriate defence, an immunity to action brought against them." (footnote omitted)
[40] The development of judicial immunity was more complex. It was bound up with the development of the law relating to excess of jurisdiction, and thus with the development of the principles governing when a judicial decision was open to collateral attack. Its history has been traced by Holdsworth. It is not necessary to examine that history in any detail, beyond noticing that the decisions of courts of record were conclusive, but those of inferior courts were open to collateral attack alleging excess of jurisdiction. Hence, while action might lie at common law for acts done in an inferior court in excess of jurisdiction, the decisions of supreme courts were final. And there was an immunity from suit for any judicial act done within jurisdiction. What is important to notice for present purposes is not the history of development of this immunity, but that both judicial immunity and the immunity of witnesses were, and are, ultimately, although not solely, founded in considerations of the finality of judgments. …
[42] In R v Skinner, Lord Mansfield said that "neither party, witness, counsel, jury, or Judge, can be put to answer, civilly or criminally, for words spoken in office". Of that immunity it has been said in Mann v O'Neill that it responds to two related considerations, "to assist full and free access to independent courts for the impartial quelling of controversies, without fear of the consequences" and "the avoidance of the re-agitation by discontented parties of decided cases after the entry of final judgment" other than by appellate processes. That view of the matter reflects the consideration that what is at stake is the public interest in "the effective performance" of its function by the judicial branch of government."
35 The submission that correction of the impugned decision on appeal overcomes the basis for the immunity is not convincing. Even though, or especially because, the decision has been corrected, the result is the lawful judgment, by definition. To reopen the material leading to the original flawed judgment (when the material was before the court in any event) on the basis that damage was caused as a result of the evidence (or the preparation of it) raises the spectre of a re-litigation of the original trial, with the same or different material. It may well be that were the evidence not to have been given in the form that it was by Mr Ballard, different evidence may have been, which evidence may have convicted Mr Griffiths. The test on appeal involves an assessment of the evidence as adduced. Re-litigation would, even in circumstances where the trial result was overturned, involve, on the authorities, an impermissible undoing of the finality of the trial. If errors occur, they must be corrected on appeal; as was done here. If witnesses have lied, then recourse is had to criminal sanctions not civil liability.
36 If the immunity is to operate, as the High Court has stated, and it is to operate consistently, then all that a witness does in court must be immune and so too all that is done by the witness out of court, which is so intimately connected with the evidence or the manner it is given, must also be immune. This is so whether the act is deliberate or inadvertent. (Cabassi, supra, at 141; D'Orta-Ekenaike at [39], [99]) In the words of Gleeson CJ in Keefe v Marks (1999) 16 NSWLR 713 at 720, when speaking of counsel's immunity:
" … the principle of immunity which applies in such a case cannot be circumvented by drawing fine distinctions between the preparation and the conduct of the case, or between the … failure to advert to the matter … while he was in Chambers and his failure to do so while he was in Court."
37 Or in the words of Starke J in Cabassi:
"But it does not matter whether the action is framed as an action for defamation or as an action analogous to an action for malicious prosecution or for deceit or, as in this instance, for combining or conspiring together for the purpose of injuring another; the rule of law is that no action lies against witnesses in respect of evidence prepared, given, adduced or procured by them in the course of legal proceedings. The law protects witnesses and others, not for their benefit, but for a higher interest, namely, the advancement of public justice. The remedy against a witness who has given or procured false evidence is by means of the criminal law or by the punitive process of contempt of court." (at 141)
38 The "breach of duty" pleaded against Mr Ballard, whether malicious or negligent, is immune from suit.
39 While Her Honour Associate Justice Harrison came to this view she expressed the view at [23], that if the "English law were applicable I would allow this matter to go to trial as it is arguable that Mr Ballard's evidence borders on being classified as fabricated." This was a reference to Darker, supra. If Darker stands for the proposition, submitted by the plaintiff, that malice or deliberate falsity during the investigation process vitiates the immunity, it is inconsistent with Australian authority and cannot be followed.
40 However, Darker does not stand for such a proposition. The House of Lords in Darker was dealing not with perjury or the conduct of a witness but with the conduct of police officers, as such, who manipulated the investigation of the offence and manipulated the material made available in the Prosecution brief and the evidence of another as part of a conspiracy to cause the plaintiffs to be charged with offences which they knew or believed to be false. This goes well beyond witness conduct and was so held. (see Darker at 459.F to 461.B and 462.F et seq)
41 I have far less confidence that, even on the English authorities, there is an arguable case against Mr Ballard for any common law claim. Her Honour is clearly correct, on authorities binding on this Court, that no arguable case is raised by the plaintiff against Mr Ballard at common law.
42 Little or no attention was paid by the parties before Her Honour as to the position of the Commonwealth, as distinct from Mr Ballard. While the claim against the Commonwealth, at common law, on the pleadings, includes vicarious liability arising from the conduct of Mr Ballard, it is not confined to that basis.
43 The pleadings as set out earlier claim damage from the Commonwealth because it did not take reasonable care in the conduct of analyses and to advise the DPP, fully and accurately, of the method and results of those analyses. Such a pleading is capable of being understood as going beyond the actions of Mr Ballard alone. It may include the procedures adopted by the Commonwealth to ensure accuracy of analysis and advice, including appropriate checks and balances.
44 Even on the question of vicarious liability, it is not clear that the immunity of a witness is enjoyed by the employer of the witness. An immunity is, in law, a defence or an immunity from suit, some kinds of which may be waived e.g. diplomatic or executive immunity. At least arguably, like privilege, it may not be available except to the individual who qualifies. Witness immunity must be pleaded.
45 There may be very good reasons, given the public policy basis for the immunity, for an employer of this kind to enjoy the same immunity but we need to avoid "the temptation to recognise the availability of the defence for new factual circumstances simply because they are closely analogous to an existing category (or cases within an existing category) without examining the case for recognition in light of the underlying rationale for the defence." (Mann v O'Neill (1997) 191 CLR 204 per McHugh J at 221)
46 While, in examining the rationale for the defence, there is strong reason to hold that an employer of an expert witness, the business of which employer is the provision of the expertise relied upon for the evidence, ought to be entitled to the benefit of the immunity, it is not beyond argument that the opposite ought to occur. By analogy, the privilege against self incrimination is available to an employee or officer of a corporation but is not available to the corporation even for the conduct of the employee or officer.
47 Even a strong probability of the immunity being available, to the Commonwealth in this case, does not allow the striking out of the case on a summary basis. The plaintiff is entitled to adduce the facts, argue the case and have his case against the Commonwealth dealt with at a hearing. The argument in favour of the immunity applicable to Mr Ballard being available to the Commonwealth is not so strong or so clear that the summary intervention of the Court is justified. In other words, even though the immunity is clear for Mr Ballard, it is not, in the case of the Commonwealth, "so obviously untenable that it cannot possibly succeed; manifestly groundless; so manifestly faulty that it does not admit of argument". (General Steel Industries v Commissioner for Railways (1964) 112 CLR 125)
48 In circumstances where there is an argument that the liability of the Commonwealth is for conduct beyond the role of witness (including, in that role of witness, the preparation of the expert analysis reports), there is an argument available that the immunity does not apply and the discretion to strike out the claim has miscarried to the extent that it relies on the immunity.