NECESSITY
Elements
1.
Done to avoid consequences which would have inflicted irreparable evil on D
or upon others whom he was bound to protect;
2.
D believed on reasonable grounds that he was placed in imminent peril; and
3.
Acts done to avoid peril must not be out of proportion to the peril to be
avoided
Cases
Dudley and Stephens (1884) 14 QBD 273
Loughnan [1981] VR 443
Rogers (1996) 86 A Crim R 542
Davidson [1969] VR 667
Martin [1989] 1 All ER 652
1)
Was or might D have been impelled to act as he did because, as a result of
what he reasonably believed to be the situation, he had good cause to fear that
otherwise death or serious physical injury would result; and if so
2)
whether a sober person of reasonable firmness, sharing the characteristics of
D, would have responded to that situation by acting as D had acted
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INSANITY
It will not perhaps, if you have ever reflected upon the matter, have escaped
your attention that a great number of people who come into a Criminal Court
are abnormal. They would not be there if they were the normal type of
average everyday people. Many of them are very peculiar in their
dispositions and peculiarly tempered. That is markedly the case in sexual
offences. Nevertheless, they are mentally quite able to appreciate what they
are doing and quite able to appreciate the threatened punishment of the law
and the wrongness of their acts, and they are held in check by the prospect of
punishment. Dixon J in Porter v R (1933) 55 CLR 182 at 188
M’Naghten Rules
1)
Every man is presumed to be sane & to possess a sufficient degree of reason to
be responsible for his crimes unless the contrary is proven
-
Onus to rebut the presumption of sanity on accused
2)
Where a man commits a criminal act under an insane delusion & is not in
other respects insane, he is under the same responsibility as if the facts with
respect to which the delusion was real
3)
It is a defence to a criminal prosecution that the accused show that, at the time
of committing the act, he was labouring under such a defect of reason from
disease of the mind, as not to know the nature & quality of the act he was
doing, or if he did not know this, that he did not know that what he was doing
was wrong.
Burden & Standard of Proof
-
Burden on accused to rebut presumption of sanity
-
Standard of proof – balance of probabilities
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Caselaw
M’Naghten’s Rules (1843) 8 ER 718; [1843-60] All ER 229
the jurors ought to be told that every man is presumed to be sane, and
to possess a sufficient degree of reason to be responsible for his
crimes, until the contrary be proved to their satisfaction: and that to
establish a defence on the ground of insanity, it must be clearly proved
that, at the time of committing the act the party accused was labouring
under such a defect of reason, from disease of the mind, as not to know
the nature and quality of the act he was doing, or, as not to know what
he was doing was wrong.

Porter (1933) 55 CLR 182

Sodeman (1936) 55 CLR 192

Stapleton (1952) 86 CLR 358

Kemp [1957] 1 QB 399

Willgoss (1960) 105 CLR 295

Quick & Paddison [1973] QB 910

Sullivan [1984] 1 AC 156

Burgess [1991] 2 WLR 1206

Cheatham (No 1) [2000] NSWCCA 282
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DIMINISHED RESPONSIBILITY
Crimes Act – s.23A
23A
Substantial impairment by abnormality of mind
(1)
A person who would otherwise be guilty of murder is not to be
convicted of murder if:
(a)
at the time of the acts or omissions causing the death concerned,
the person’s capacity to understand events, or to judge whether the
person’s actions were right or wrong, or to control himself or
herself, was substantially impaired by an abnormality of mind
arising from an underlying condition, and
(b)
the impairment was so substantial as to warrant liability for
murder being reduced to manslaughter.
(2)
For the purposes of subsection (1) (b), evidence of an opinion that an
impairment was so substantial as to warrant liability for murder being
reduced to manslaughter is not admissible.
(3)
If a person was intoxicated at the time of the acts or omissions causing
the death concerned, and the intoxication was self-induced intoxication
(within the meaning of section 428A), the effects of that self-induced
intoxication are to be disregarded for the purpose of determining
whether the person is not liable to be convicted of murder by virtue of
this section.
(4)
The onus is on the person accused to prove that he or she is not liable to
be convicted of murder by virtue of this section.
(5)
A person who but for this section would be liable, whether as principal
or accessory, to be convicted of murder is to be convicted of
manslaughter instead.
(6)
The fact that a person is not liable to be convicted of murder in respect
of a death by virtue of this section does not affect the question of
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whether any other person is liable to be convicted of murder in respect
of that death.
(7)
If, on the trial of a person for murder, the person contends:
(a)
that the person is entitled to be acquitted on the ground that the
person was mentally ill at the time of the acts or omissions causing
the death concerned, or
(b)
that the person is not liable to be convicted of murder by virtue of
this section,
evidence may be offered by the prosecution tending to prove the
other of those contentions, and the Court may give directions as to
the stage of the proceedings at which that evidence may be
offered.
(8)
In this section:
underlying condition means a pre-existing mental or physiological
condition, other than a condition of a transitory kind.
Cases
(a)
Generally

Veen (1979) 143 CLR 458

Thompson (1988) 36 A Crim R 223
(b)
Abnormality of mind

Byrne [1960] 2 QB 396

Jones (1986) 22 A Crim R 42
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Purdy [1982] 2 NSWLR 964
Defence under s23A requires D to show:
a.
that his state of mind when he carried out the acts or omissions were
abnormal;
b.
that the abnormality can be attributed to one of the aetiological factors
specified in the section; and
c.
the abnormality substantially impaired his mental responsibility for the acts or
omissions

McGarvie (1986) 5 NSWLR 270

Tandy [1989] 1 All ER 267
Tumanako (1992) 64 A Crim R 149
D must establish 3 matters:
1)
At the time of the act causing death he was suffering from an abnormality of
mind;
2)
Such abnormality arose from one or more several causes specified in s23A;
3)
That such an abnormality of mind was such as substantially impaired the
mental responsibility of the accused for what he did
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Cheatham (No 2) [2002] NSWCCA 360
“It is necessary for the judge to tell the jury that in determining whether the
accused was suffering such abnormality of mind as substantially impaired his
mental responsibility for the acts or omissions (in the present case the
stabbings) they must take into account the perceptions of events of the accused
and the nature and extent of any impairment of his perceptions, his capacity to
understand events and his ability or capacity to form a sensible judgment as to
whether his actions were right or wrong.”

Christov [2006] NSWSC 972

Potts [2012] NSWCCA 229
(c)
Substantial impairment of mental responsibility

Lloyd [1967] 1 QB 175

Trotter (1993) 68 A Crim R 536
(d)
Proof

Walton [1978] AC 788

Tumanako (1992) 64 A Crim R 149
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REVISION QUESTIONS
Question 1
Rowena needed money urgently to pay off a debt to Richard. Rowena went into her
flatmate Greg’s room and took the $80 that was in his wallet and his gold watch.
Rowena then went and pawned the watch at the local pawn shop. Rowena intended to
repay Greg the money when she got paid the following week.
Rowena still did not have enough money, so she asked her friend Kim for money.
When Kim said no, Rowena told her that she would beat her ‘black and blue’ unless
she got some money.
Kim was frightened and went to her friend John for help. He suggested that they steal
some computers from the local computer shop. Kim and John went into the computer
shop and started to grab computers to steal. The shop assistant Andrew yelled at them
to stop. John pulled out a knife and stabbed Andrew, then Kim & John ran away. Kim
knew that John always carried a knife. Andrew was in hospital for three weeks with
injuries from John.
Discuss the criminal liability of Kim, Rowena & John.
Question 2
Michael was at home and started to receive threatening messages over the phone. The
person said things like ‘I’m going to get you’ and ‘Watch out, there is danger about’.
Michael began to feel very afraid. Later that night he decided to put the garbage out.
As he was walking towards the garbage bin, a person started to walk towards him.
The person said ‘I’m here now, and I’ll do what I promised.’
Michael freaked out and whammed the garbage bag onto the person’s head. When the
person collapsed onto the ground, Michael kicked him several times.
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It turned out that the person Michael attacked had nothing to do with the threatening
phone calls. The person that Michael injured was called George, and was a painter,
who was talking into his mobile phone at the time that Michael saw him. As a result
of Michael attacking him, George had a few broken ribs.
Discuss Michael’s criminal liability. Would your answer be different if George had
died as a result of the attack?
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