12 The defence case concedes that I would find that the accused committed the act causing death and that it was accompanied by the necessary intention. However it is contended that I would be satisfied that the accused was mentally ill at the relevant time and so I should return the special verdict provided by s 38 of the Act, that he is not guilty by reason of mental illness. This requires a consideration as to whether, at the time of the killing, the accused was labouring under a defect of reason, from disease of the mind, as not to know the quality and the nature of the act he was doing, or that if he did know, that he did not know what he was doing was wrong: R v M'Naghten (1843) 8 ER 718; R v Porter [1933] HCA 1; 55 CLR 182. The onus of proof in respect of this issue is upon the accused and the standard of proof is the balance of probabilities: Mizzi v The Queen [1960] HCA 77; 105 CLR 659; R v Ayoub [1984] 2 NSWLR 511.
13 It is the second leg of the test in M'Naghten that is in issue in this case, that is whether the accused did not know what he was doing was wrong. It is not to the point whether he knew what he was doing was legally wrong. Regina v Cheatham [2000] NSWCCA 282.