An outcome which raises concern

Suppose that the issue in a case is identification.  There are 2 identification parades though the defendant is only "lined up" in one of them.  At neither parade does the prosecution witness "pick out" the defendant and actually picks out others (including a Police "stand in").  This material is not revealed to the defendant as part of the pre-trial disclosure required by law.  Has the defendant's right to a fair trial (Article 6) been breached?  You might think that the answer was YES.  However, it seems that the real test is whether, in all the circumstances of the trial, there was a real possibility that the jury would have reached a different verdict had the disclosure been made.  So said the Supreme Court of the U.K. in McInnes v H.M. Advocate [2010] UKSC7.  Although this appeal came from Scotland, there is no particular reason to suppose that English courts would have a different view.  The decision appears to give appeal courts a free hand to dismiss any appeal no matter how outrageous the prosecution failure by simply substituting its own view of the case for that of a jury.