[2] The basic rule is that under our system the accused is entitled to a fair trial or, at least, a trial which is as fair as the court can make it: Glennon [1992] HCA 16; (1992) 173 CLR 592 at 616. The ability of criminal defence advocates no doubt varies widely; the law does not guarantee an accused person representation by the best counsel. These observations are not intended as a reflection on the ability of the counsel who appeared at the trial of this applicant; they have to do with the general question of how great must be the degree of incompetence proved, to warrant setting aside a verdict. A clear mistake made by counsel, although not capable of being, without hyperbole, described as demonstrating an "extremely high level of incompetence" could possibly be of such significance that the verdict cannot stand; for example, counsel might in a complicated case simply have forgotten to call an independent witness, or tender documents, where the evidence not adduced was of such a kind as to throw real doubt on the Crown's case. Similar considerations apply where the error is said to be one of a solicitor, in not taking proper steps to prepare the defence.