The rule, as appears from the passage cited is not to be regarded as absolute in the sense that it must be applied rigidly to every observation which a judge might make of a party during the course of a trial outside the witness box. Something will depend no doubt on the circumstances of the particular case and upon the significance of the particular observations. It is clear however that where the judge makes observations of the actions or demeanour of a party, which actions and demeanour are not observable by counsel, and makes use of those observations in a way which has a significant influence upon his decision of the case, he is required in justice before making such use of those observations to make those observations and the possibility of his using them in the course of his judgment known to counsel at a stage of the hearing at which counsel still has an opportunity of dealing with them in a proper and effective way.
16 These principles have been followed in later cases. See Marelic v Comcare (1993) 47 FCR 437, Government Insurance Office of New South Wales v Bailey (1992) 27 NSWLR 304, In the marriage of F and M Chehab (1993) 16 FLR 477 and In the marriage of Zantiotis (1993) 113 FLR 182.
17 In Bailey's Case, Kirby P said (at 313):
So long as the conventional theory reigns that observations of a party or other witness are an important and legitimate element in curial decision making, it is appropriate to permit at least the observations to be taken into account which occur inside the courtroom. However, this conclusion leaves the question of notification to the parties and their representatives where the observations have occurred, as here, outside the actual period of the trial and when the person being observed is at the back of the court behind the representatives of the parties who thus have no opportunity to observe the features in question and by interrogation, evidence or advocacy, to persuade the decision maker to a different view about them than has been formed….
18 Before us, the respondent's submissions were put by Mr McIntyre SC, who represented the respondents who were the defendants in the first action. His submissions were adopted by Mr Ronzani, representing the respondents who were the defendants in the second action.
19 It was submitted that the trial had progressed to such a stage that it was too late for the appellant to have done anything in response to Mr Kelleher's invitation which was to take account of the appellant's conduct in the courtroom during the time of final addresses at trial. I cannot accept this submission. Mr Kelleher's invitation raised two matters: (1) what was the appellant doing that was inconsistent with the evidence; and (2) was there any explanation for it.
20 In the passage from Bailey's case that I have set out, Kirby P referred (at 313) to the opportunity of a party who has not, through his or her counsel, observed the conduct in question to persuade the decision maker to a favourable view about it "by interrogation, evidence or advocacy".
21 The trial in the present case was not so far advanced that any of those three opportunities were foreclosed. Leave would have been required to re-open the evidence but it is inconceivable that such leave would have been refused if sought, whether the dispute was about what happened or as to its explanation.
22 It is convenient to pass next to what is logically the final submission of the respondents. It was submitted that her Honour's observation of the appellant in Court did not bear upon her assessment of him as a witness of little credit. In Stead v The State Government Insurance Commission (1986) 161 CLR 141 at 145 the High Court said that:
… not every departure from the rules of natural justice at a trial will entitle the aggrieved party to a new trial....Where, however, the denial of natural justice affects the entitlement of a party to make submissions on an issue of fact, especially when the issue is whether the evidence of a particular witness should be accepted, it is more difficult for a court of appeal to conclude that compliance with the requirements of natural justice could have made no difference. True it is that an appeal to the Full Court from a judgment or order of a judge is by way of rehearing and that on hearing such an appeal the Full Court has all the powers and duties of the primary judge, including the power to draw inferences of fact. However, when the Full Court is invited by a respondent to exercise these powers in order to arrive at a conclusion that a new trial, sought to remedy a denial of natural justice relevant to a finding of fact, could make no difference to the result already reached, it should proceed with caution. It is no easy task for a Court of Appeal to satisfy itself that what appears on its face to have been a denial of natural justice could have had no bearing on the outcome of the trial of an issue of fact. And this difficulty is magnified when the issue concerns the acceptance or rejection of the testimony of a witness at the trial.