"In a number of cases, Australian courts have indicated that a sentence may be reduced in the case of a manifest or excessive disparity, even though it may result in the reduction of a sentence to a point where, standing alone, it might be regarded as inadequate: see, eg, Lowe's case, per Mason J (at 613-614); R v Goldberg [1959] VicRp 52; (1959) VR 311 at 312; R v Maslen (1995) 79 A Crim R 199 at 208; R v Hodges (1997) 95 A Crim R 85 at 96.
A narrower view than that taken by Mason J was expressed by Brennan J in Lowe v The Queen (at 617) whilst in Robertson v The Queen (1989) 44 A Crim R 224, this Court, differently constituted, expressed the view that the parity argument must give way when a patently inadequate sentence has been imposed on a co-offender. With respect, it is one thing to decline to lower an otherwise appropriate sentence to the level of a patently inadequate sentence, but it is quite another to decline to make any reduction at all, particularly when the higher sentence is not such as to be at the lowest level of the appropriate range and could, on appeal, fairly be lowered to a level 'which might be regarded as inadequate'. The latter, it would seem, was the approach adopted by Anderson J in Capper v The Queen (1993) 69 A Crim R 64 at 74. He did not express the view that the parity argument must fail when a patently inadequate sentence has been imposed on a co-offender. See also Thorne v The Queen (unreported, Court of Criminal Appeal, WA, Full Court, Library No 990154, 29 March 1999), in which the view expressed by Anderson J was adopted. See also Ruane v The Queen (1979) 1 A Crim R 284 at 286 and R v Tisalandis (at 437-440) (cf Street CJ (at 431-432) and Nagle CJ at CL (at 441)). The application of this test would give parity a restricted application.
In my opinion, the better view, having regard to the underlying principle, is that Courts of Criminal Appeal may intervene in the event of there being a manifest disparity in the sentences imposed upon co-offenders, notwithstanding that they regard the sentences imposed upon the applicant as falling within the range of the exercise of a sound discretionary judgment and notwithstanding that they regard the co-offenders' sentences as being inadequate. As indicated by Gibbs CJ and Mason J in Lowe's case (at 610 and 611 respectively), 'marked disparity' is itself a ground for reducing the more severe sentence, provided, of course, that the disparity is such as to give rise to a justifiable sense of grievance: see also R v MacGowan (1986) 42 SASR 580 at 583, per King CJ. But it does not follow from this that the court will reduce the higher sentence so that it equates in all respects to the sentence imposed on the co-offender. The position was explained by Gleeson CJ when sitting in the Court of Criminal Appeal in New South Wales in R v Reardan (1996) 89 A Crim R 180 at 182. He said: '[J]ustice does not require that the court should seek, so far as possible, to match the sentence imposed upon the appellant with that imposed upon [the co-offender]. Rather, it is a matter to be taken into account in a broad discretionary exercise.'
This is the discretion of which Gibbs CJ also spoke in Lowe's case: see also R v Cox (1991) 55 A Crim R 396 at 401-402, per Thomas J."