65 However, as Gleeson CJ, Gummow and Kirby JJ observed in the recently decided case of Fox v Percy [2003] HCA 22 at pars 26 to 28 these cases did not constitute a departure from established doctrine. They were simply a reminder of the limits under which appellate Judges typically operate when compared with trial Judges. The established doctrine did not, and could not, derogate from the obligation of courts of appeal, in accordance with the relevant legislation, to perform the appellate function as established by Parliament; that is, such courts must conduct the appeal by way of rehearing. If, making proper allowance for the advantages of the trial Judge, they conclude that an error has been shown, they are authorised, and obliged, to discharge their appellate duties in accordance with the statute. In particular cases incontrovertible facts or uncontested testimony will demonstrate that the trial Judge's conclusions are erroneous, even when they appear to be, or are stated to be, based on credibility findings.