Miscarriage of justice and strength of the prosecution case

Miscarriages of justice may be thought of as having two roles to play in criminal procedure. The first is as a ground of appeal. The second is where a miscarriage of justice is not "substantial", and on this ground the appellate court may dismiss the appeal (called "applying the proviso").

Miscarriages of justice are usually "substantial". They arise from fundamental departures from proper procedure. Once the appellate court is satisfied that there has been a miscarriage of justice that amounts to a fundamental departure from proper procedure, it will not matter that the evidence in support of conviction was overwhelming. The conviction will be quashed. Usually a re-trial will be ordered.

These observations, which are an intentional simplification of the law, are illustrated by the High Court of Australia, in Subramaniam v R [2004] HCA 51 (10 November 2004). The Court cited Wilde v The Queen (1988) 164 CLR 365 at 373 (per Brennan, Dawson and Toohey JJ):
:
"The proviso has no application where an irregularity has occurred which is such a departure from the essential requirements of the law that it goes to the root of the proceedings. If that has occurred, then it can be said, without considering the effect of the irregularity upon the jury's verdict, that the accused has not had a proper trial and that there has been a substantial miscarriage of justice ...
There is no rigid formula to determine what constitutes such a radical or fundamental error. It may go either to the form of the trial or the manner in which it was conducted."

Reference was also made to TKWJ v R (2002) CLR 124, 147 [73], where McHugh J said:

"…in most cases of misdirection on facts, the appellant has the onus of establishing a misdirection, that it might have affected the verdict and that, if it had not been made, the jury might have acquitted the appellant. In some undefined categories of cases, however, the irregularity may be so material that of itself it constitutes a miscarriage of justice without the need to consider its effect on the verdict."