Mr Rares pointed out that Ms McIllhatton had sworn an affidavit and that the affidavit had been read in the proceedings (although it did not deal with her reasoning processes or motivation). Mr Rares contended that, in accordance with the passage in Recher, cross-examination could not be limited, so long as it was confined to a relevant issue.
I do not think that the principle applied in Recher is applicable to the circumstances of the present case. In Recher, a policy of insurance provided that the amount of all losses under the policy should be assessed by the insurer's auditors. The auditors' certificates were put in evidence in one arbitration and an auditor was called as a witness to state that he was satisfied that the losses had in fact been sustained. It was in this context that the ruling was made.
The extent to which an auditor, or an arbitrator agreed between the parties, may be cross-examined involves, in my view, different considerations to those applicable to a judicial officer, or to a Tribunal member clothed with the statutory immunity of a judicial officer. As Samuels J.A. said in Zanatta v McCleary (at 239), the policy reasons for the immunity of judges are stated concisely in the passage cited earlier from the judgment of Cleasby B. in the Duke of Buccleuch's Case. Cleasby B. specifically distinguished between the position of a judge and that of an arbitrator (the position of the auditor in Recher being different again). In a particular case it may be appropriate, or even necessary for a judge (or a Tribunal member having the immunity of a judge) to give evidence about the course of events occurring in his or her courtroom: compare Xiang Sheng Li v Refugee Review Tribunal, Moore J, Federal Court of Australia, 14 December 1994, unreported, at 14. If that were sufficient to expose the judge to cross-examination on his or her reasoning processes or motivation, the rationale for the immunity, if not destroyed, would be severely undermined. The position might be different if the judge chooses to give evidence in chief about his or her reasoning processes or motivation. However, this is not the present case and I prefer to express no view about it.
Mr Rares' second argument proceeded from the proposition that an allegation of actual bias, if made out, involves the Tribunal in what is commonly described as a jurisdictional error. That being so, Mr Rares argued, evidence relating to the member's motivation cannot be characterised as infringing the immunity enjoyed by her "in the performance of [her] duties as a member", within the meaning of s.60(1) of the Administrative Appeals Act 1975. It follows that cross-examination of the member can take place where the objective is to demonstrate actual bias.
The difficulty with this argument, as Mr Basten pointed out, is that it proves too much. It is not only bias on the part of a Tribunal that establishes jurisdictional error. Such error may be constituted, for example, by a failure to comply with the requirements of procedural fairness or natural justice, a misconstruction of the governing legislation, or a failure to take account of relevant considerations: Anisminic Ltd v Foreign Compensation Commission [1969] 2 AC 147 (HL), at 171; The Queen v Dunphy; ex parte Maynes (1978) 139 CLR 482, at 496; BHP Petroleum Pty Ltd v Balfour (1987) 71 ALR 711 (H Ct). The point has recently been illustrated by two decisions of the New South Wales Court of Appeal, holding that a denial of procedural fairness in the course of sentencing is a jurisdictional error, amounting to a refusal to exercise jurisdiction: Kopuz v District Court of New South Wales (1992) 28 NSWLR 232; Parker v Director of Public Prosecutions (1992) 28 NSWLR 282.
If Mr Rares' argument were correct, any allegation of procedural unfairness and most allegations of error of law, would make the Tribunal member compellable (not merely by way of cross-examination after having chosen to give evidence in chief) to give evidence about his or her reasoning processes or motivation in making a decision. This would, in my view, effectively negate the purpose underlying the grant of statutory immunity in s.166G(1) of the Migration Act 1958. The grant of protection and immunity is expressed to extend to a member "in the performance of [her] duties as a member". In my view, without stating the scope of the immunity exhaustively, where the member embarks on an inquiry that the Tribunal is authorised to undertake, conduct in the course of that inquiry is properly characterised as "performance of [the member's] duties as a member". This accords with the broad view taken by the High Court of the phrase "performance of any duty": Canadian Pacific Tobacco Co Ltd v Stapleton (1952) 86 CLR 1, at 6; Herscu v The Queen (1991) 173 CLR 276, at 282-283. The statutory immunity therefore applies notwithstanding that an allegation of bias is made in relation to the Tribunal.
Mr Rares referred me to Electronic Rentals Pty Ltd v Anderson (1971) 124 CLR 19. There the Court refused special leave to appeal from a decision of the New South Wales Court of Appeal (Ex parte Electronic Rentals Pty Ltd; Re Anderson (1970) 72 SR (NSW) 532). Windeyer J., with whom Barwick C.J. and Owen J. agreed, held that in criminal proceedings in which the validity of certain informations was challenged, it was competent for the justices of the peace who signed the informations to give evidence of the circumstances in which they came to do so. That evidence was that the justices had been misled and had not read the documents they were asked to sign (and in one case the justice thought he was merely witnessing legal document). Windeyer J. referred (at 37) to the Duke of Buccleuch's Case as authority for the proposition that an arbitrator
"may be questioned as to what matters were presented for his consideration. He cannot be asked what passed in his mind leading him to exercise his discretion in the way he did in relation to any matter he had to decide."
His Honour considered that this principle did not apply to the case before him
"Their evidence was not of what led them to exercise a discretion. What they said was that they did not exercise any discretion at all - in effect that they did not know what they were doing beyond signing their names. They were told, they said, that their signatures were required as witnesses: that is to say that they were asked to authenticate the acts of another person. But what they actually signed were summonses purporting to be their own acts, commands
issued by them as a result of informations duly laid. They were, they say, misled. I cannot agree that their evidence to the magistrate was in the circumstances inadmissible..."