The principles have been helpfully set out by Charles JA (with whom Winneke P and Hayne JA, as his Honour then was, agreed) in R v Clarke [1996] VICSC 30; [1996] 2 VR 520 at 522, after a careful consideration and analysis of the cases. I summarise those principles as follows:
(i) An appeal by the Crown should be brought only in the rare and exceptional case to establish some point of principle.
(ii) Occasions may arise for the bringing of a Crown appeal:
(a) when a sentence reveals such manifest inadequacy or inconsistency in sentencing standards as to constitute an error in principle;
(b) where it is necessary for a court of criminal appeal to lay down principles for the governance and guidance of courts having the duty of sentencing a convicted person;
(c) to enable the courts to establish and maintain adequate standards of punishment for crime;
(d) to enable idiosyncratic views of individual judges as to particular crimes or types of crimes to be corrected;
(e) to correct a sentence which is so disproportionate to the seriousness of the crime as to shock the public conscience; and
(f) to ensure, as far as the subject matter permits, that there will be uniformity of sentencing.
(iii) When, in response to a Crown appeal, the court decides to resentence an offender it ordinarily gives recognition to the element of double jeopardy involved by imposing a sentence that is somewhat lesser than the sentence it considers should have been imposed at first instance.
(iv) The appellate court has an over-riding discretion which may lead it to decline to intervene even if it concludes that error has been shown.
These principles were adopted by this Court in R v Eisenach [2011] ACTCA 2 (at [8] to [10]).
In addition, the court has to approach the appeal in accordance with principles applicable to all appeals against sentence, namely:
(v) The court is not hearing the matter anew and is not entitled to substitute its own opinion for that of the sentencing judge merely because it considers the sentence inadequate or excessive. The court only interferes if there is an error of fact or law by the sentencing judge of the kind referred to in House v The King [1936] HCA 40; (1936) 55 CLR 499 at 504-5, or where there is such manifest inadequacy or excess in sentence as to indicate error.