(a) A fundamental distinction is drawn between the approach of an appellate court in two different classes of cases - the drawing of inferences from admitted facts or facts found by the trial judge, on the one hand, and findings which depend upon the view taken of conflicting oral testimony, on the other hand (Fox v Percy [2003] HCA 22; (2003) 214 CLR 118 (Fox v Percy) at 146 [88] (McHugh J); Brunskill v Sovereign Marine & General Insurance Co Ltd [1985] HCA 61; (1985) 59 ALJR 842 at 844 (the Court); State Rail Authority of New South Wales v Earthline Constructions Pty Ltd (in liq) [1999] HCA 3; (1999) 73 ALJR 306 (SRA v Earthline) at [93] (Kirby J)). ... The assessment of a witness' state of mind has also been said to fall within the second category of cases: Bendigo at 544 [141] (Heydon J) (citing with approval Nocton v Lord Asburton [1914] AC 932 at 957 (Viscount Haldane LC)).
(b) With respect to cases falling within the first class, the principle is that expressed by Gibbs ACJ, Jacobs and Murphy JJ in Warren v Coombes [1979] HCA 9; (1979) 142 CLR 531 (Warren v Coombes) at 551, namely:
...the established principles are, we think, that in general an appellate court is in as good a position as the trial judge to decide on the proper inference to be drawn from facts which are undisputed or which, having been disputed, are established by the findings of the trial judge. In deciding what is the proper inference to be drawn, the appellate court will give respect and weight to the conclusion of the trial judge, but, once having reached its own conclusion, will not shrink from giving effect to it.
In so holding, the High Court rejected the approach of judicial restraint adopted in some of the authorities which required that error be demonstrated in the decision of the primary judge before the appellate court would reverse findings of fact or inferences from fact provided that both inferences were open: see further the detailed and helpful analysis of the authorities by Dodds-Streeton JA in Kelso v Tatiara Meat Co Pty Ltd [2007] VSCA 267; (2007) 17 VR 592 (Kelso) at [65]-[95] (with whose reasons the remainder of the Court agreed).
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(d) It may also be the case that appealable error exists by reason of a failure at first instance to determine the case upon a proper consideration of the real strength of the body of evidence presented by the losing party and the basis upon which the evidence of a witness was found unreliable is too fragile or slight: SRA v Earthline at [63]-[64] (Gaudron, Gummow and Hayne JJ), [93]-[94] (Kirby J) and [148]-[155] (Callinan J); cf eg Hasler v Singtel Optus Pty Ltd [2014] NSWCA 266; (2014) 311 ALR 494 (Hasler) at 525 [157] (Leeming J (with whose reasons the remainder of the Court agreed)).
(e) Underpinning the authorities as to the second class of cases is a continuing appreciation of the advantage which the primary judge may enjoy despite the availability today of complete transcripts of evidence and argument, the trend to giving evidence in chief by affidavit, and a growing understanding of the fallibility of the judicial evaluation of credibility from the appearance and demeanour of witnesses, particularly in the stressful environment of the courtroom and in an increasingly culturally diverse society: SRA v Earthline at [87]-[88] (Kirby J) ...
(f) A finding that oral testimony is disbelieved will almost invariably be express. However, it cannot be assumed that every consideration influencing the primary judge's assessment of credibility, including her or his impressions of the witness, will find expression in the reasons. In discharging the appellate function, account should also be taken for unexpressed considerations and impressions: Fox v Percy at 132 [41] (Gleeson CJ, Gummow and Kirby JJ)...
(g) Finally, the weight to be given to the advantage enjoyed by the primary judge must, of necessity, be affected to some degree by the circumstances of the individual case...