Section 23 of the Crimes Act 1900 deals with provocation in relation to murder, which can operate to reduce murder to manslaughter.
Where the question arises as to possible provocation by a person other than the victim, directions to the effect of those given by Brooking J in R v Kenney  2 VR 470 may be appropriate.
Where there is some reasonable evidence of provocation, it must be left to the jury, even though it has not been raised by the defence and even though the accused has not given evidence of actual loss of self control: Parker v The Queen (1964) 111 CLR 665 at 681–682; Lee Chun-Chuen v The Queen  AC 220 at 232.
The question of whether provocation should be left to the jury should be decided upon a view of the facts most favourable to the accused: Holmes v DPP  AC 588 at 597.
Normally, self induced provocation will be insufficient, yet provocation should be left if the response of the deceased to the accused’s own provocative acts may have been out of proportion to that which might naturally have been expected: Edwards v The Queen  AC 648.
Provocation requires a reaction by the accused to the conduct of the deceased (including grossly insulting words or gestures) which occurs in his or her sight or hearing. The provocative incident must be one which directly involves the accused and the deceased, although the actual element of provocation may not be directed intentionally or specifically against the accused: R v Quartly (1986) 11 NSWLR 332 at 338; R v Davis (1998) 100 A Crim R 573.
Some apparently innocuous words and conduct on the part of the deceased in the presence of the accused could, when considered in the light of the whole history of their relationship (including matters not occurring in the presence of the accused) amount to provocation: R v R (1981) 28 SASR 321; Moffa v The Queen (1977) 138 CLR 601 at 616; R v Peisley (1990) 54 A Crim R 42.
The loss of self control may be due to fear, anger or resentment, but must be present at the time of the killing. Conduct giving rise to a sense of grievance or revenge, such as that when the opportunity presents it is taken, will not suffice: Van Den Hoek v The Queen (1986) 161 CLR 158 at 167; R v Croft  1 NSWLR 126 at 140. However, there is no requirement that the killing immediately follow upon the provocative act or conduct of the deceased. The loss of self control can develop after a lengthy period of abuse, and without the necessity for a specific triggering incident: R v Muy Ky Chhay (1994) 72 A Crim R 1.
The ordinary person is a person of the same age and maturity as the accused. “On balance, it seems to us that the preferable approach is to attribute the age of the accused to the ordinary person of the objective test, at least in any case where it may be open to the jury to take the view that the accused is immature by reason of youthfulness”, see: Stingel v The Queen (1990) 171 CLR 312 at 331. Considerations of sexual preference, racial background, physical disability and the like, while relevant to the assessment of the gravity of the conduct said to constitute provocation, are not to be imputed to the ordinary person: Stingel v The Queen; Baraghith v The Queen (1991) 54 A Crim R 240. The meaning of the expression “an ordinary person” and “a person placed in the position of the accused” in s 23(2)(a) and (b) of the Crimes Act 1900 were considered by the High Court in Green v The Queen (1997) 191 CLR 334.
The ordinary person is to be assumed to have been sober and unaffected by drugs: R v Cooke (1985) 16 A Crim R 304. In considering whether the accused did lose control as the result of provocative behaviour, his or her state of sobriety and personal characteristics are to be taken into account:
“Provocation … is as available to an intoxicated accused as to a sober accused. If an intoxicated accused has in fact lost his or her self control, it becomes a question of fact for the jury whether that loss of self control was caused by the deceased’s words or conduct, or solely by the inflammatory effects of drink or drugs.”: R v Cooke (at 314).
A question arises to the possible effect of Pt 11A of the Crimes Act 1900 in this context.
As to continuance of provocation covering two incidents, see: Masciantonio v The Queen (1995) 183 CLR 58. Where the deceased’s death is the result of the infliction of injury by the accused upon the deceased on two occasions, the question of whether, in the sequence of events, the accused having lost his or her self control had regained it so that the continued infliction of injury was in fact no longer provoked, is not a question to be answered by reference to the ordinary person. It is to be answered by reference to the conduct of the accused and to common experience of human affairs.
As to the relationship between provocation and lies, see: R v Richens (1994) Cr App R 43.
The final issue which the Crown must establish in order to prove that the accused is guilty of murder is that the accused was not acting under provocation when [he/she] killed [the deceased]. It is not for the accused to prove that [he/she] was acting under provocation but for the Crown to prove that beyond reasonable doubt that [he/she] was not.
If the Crown satisfies you beyond reasonable doubt that all the other elements of murder have been established beyond reasonable doubt and the accused was not provoked to do what [he/she] did, the appropriate verdict is “guilty of murder”. If, however, the Crown does not satisfy you that [he/she] was not provoked, the accused will be “not guilty of murder” but “guilty” of the less serious offence of manslaughter (that is, manslaughter by provocation).
How then do you determine whether the accused was (or may have been) provoked to do what [he/she] did?
The law provides that an [act/omission] causing death is an act [done/omitted] under provocation where —
The [act/omission] is the result of a loss of self control on the part of the accused that was induced by any conduct of [the deceased] (including grossly insulting words or gestures) towards or affecting the accused; and
That conduct of [the deceased] was such that it could have induced an ordinary person in the position of the accused to have so far lost self control as to have formed an intent to kill, or to inflict grievous bodily harm upon, [the deceased], whether the conduct of [the deceased] occurred immediately before the [act/omission] causing death, or at any previous time.
… [where raised, intoxication must be taken into account when considering question one, but not when considering question two].
These principles of law require you to consider the following question or questions. The first question is — “May [the deceased’s] conduct, that is, the things [he/she] did or said, or both, have induced (that is, caused) the accused to lose [his/her] self control?”.
The conduct or words of [the deceased], which allegedly induced the loss of self control on the part of the accused, need not have occurred immediately before the act causing death but may have occurred at any previous time and may be a course of conduct over a period of time, even years, or may include a course of conduct over a period of time together with other conduct immediately prior to the act causing death.]
There must be a causal connection between the conduct of [the deceased] and the loss of self control by the accused. In determining whether there was such a connection, you must consider the gravity of the alleged provocation so far as the accused is concerned. There are relevant matters raised in this case by the evidence.
You must appreciate that conduct which might not be insulting or hurtful to one person may be extremely hurtful to another because of that person’s age, sex, race, ethnic or cultural background, physical features, personal attributes, personal relationships or past history … [refer to the special characteristics of the accused raised by the evidence. This would include in an appropriate case the “battered wife syndrome”. It will be necessary to relate any expert evidence as, for example, with regard to the “battered wife syndrome” to the particular facts and circumstances of the subject case].
It is proper that you view the words or conduct in question as a whole and also in the light of any history or disputation between [the deceased] and the accused since particular acts or words which considered separately could not amount to provocation may, in combination or cumulatively, be enough to cause the accused to lose [his/her] self control in fact.
That is quite different from a deliberate act of vengeance, hatred or revenge, and likewise quite different from a consideration of whether in the light of [his/her] conduct [the deceased] got [his/her] just deserts.
If you are satisfied beyond reasonable doubt that the answer to that question is “No”, then the Crown has negatived provocation and providing you are satisfied beyond reasonable doubt as to all the elements of murder to which I have earlier referred, the appropriate verdict is “guilty of murder”.
If, however, the answer is “Yes”, then you must turn to the second question, which is — “May the conduct of [the deceased] have induced an ordinary person in the position of the accused to have so far lost self control as to have formed an intent to kill, or inflict grievous bodily harm on [the deceased]?”.
An “ordinary person” is simply one who has the minimum powers of self control expected of an ordinary citizen who is sober and of the same age and consequent level of maturity as the accused.
When one speaks of the effect of provocation on an ordinary person in the position of the accused, that phrase means an ordinary person who has been provoked to the same degree of severity and for the same reason as the accused.
In the present case, this translates to a person with the minimum powers of self control of an ordinary person, as described earlier, who is subjected … [for example, to a sexual advance by the victim which is aggravated because of the accused’s special sensitivity to a history of violence and sexual assault within the family]. [None of the attributes or characteristics of a particular accused will be necessarily irrelevant to an assessment of the content and extent of the provocation involved in the relevant conduct].
This question requires you to take full account of the sting of the provocation actually experienced by the accused, but eliminates from your consideration an extraordinary response (if such there be) by the accused to the provocation actually experienced.
You should understand that when you are dealing with this question you are considering the possible reaction of an ordinary person in the position of the accused, not [his/her] inevitable or even probable reaction, but [his/her] possible reaction.
If the answer to this question is “No”, the Crown has negatived provocation and all the other elements of murder have been established beyond reasonable doubt, the appropriate verdict is “guilty of murder”.
If the answer is “Yes”, the Crown has failed to negative provocation and the appropriate verdict is “not guilty of murder but guilty of manslaughter”.