1. Defences
Insanity

2. The M’Naghten Rules
• The rules insanity are based on the
M’Naghten Rules (1843):
• D suffered from extreme paranoia. Tried
to kill England's PM, but instead shot and
killed Peel's secretary. D found not guilty
of murder, but committed to a mental
hospital because of his mental state. The
main rule created by this case was:
• ‘in all cases every man is presumed to be
sane and to possess a sufficient degree of
reason to be responsible for his crimes’.

3. Insanity
• For the defence of insanity to be
established …..
• The defendant must be ‘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 if
he did know it, that he did not know he
was doing what was wrong.’

4. 3 Elements?.....
• So three elements need to be proved:
• 1) Defect of Reason
• 2) Which must be the result of a disease
of the mind
• 3) Causing the defendant not to know the
nature and quality of his act or not to know
he was doing wrong.
• The burden of proof is on the defence

5. Defect of reason
• The defendants powers of reasoning
must be impaired. If the defendant is
capable of reasoning, but failed to use
the power, this is not a defect of
reason- CLARKE
• Defect of reason must be more than
just confusion or absent-mindedness

6. Clarke (1972)
Mrs Clarke, absent-mindedly placed items
into her bag whilst shopping. She had no
recollection of this. Medical evidence given
at her trial stated she was suffering from
depression and was diabetic. The trial
judge ruled that this raised the defence
of insanity. Held:
Short periods of absent-mindedness fell
far short of amounting to a defect of
reason.

7. Disease of the Mind
• Defect of Reason must be due to Disease
of the Mind. This can be a mental disease
or a physical which affects the mind.
• Kemp, Sullivan, Hennessy, Burgess, Quick
• Kemp (1956): Hardening of the arteries
caused loss of control during which the
defendant attacked his wife with a
hammer. This was an internal condition and
a disease of the mind.

8. Sullivan (1984)
• The defendant kicked and injured a man
during a minor epileptic fit. The trial judge
ruled that he was prepared to direct the
jury on the defence of insanity.
• The House of Lords held that epilepsy was
a disease of the mind because the
defendant's mental faculties were
impaired to the extent of causing a defect
of reason. Disease can be any part of the
body provided it has an effect on the mind.

9. Hennessy (1989)
• Appellant had stolen a car and was stopped by
the police. He was a diabetic and not been
taking his insulin. The appellant had no
recollection of taking the car. The trial judge
ruled that the appropriate defence would be
insanity. The appellant changed his plea to
guilty and then appealed against his conviction.
Held:
•
Appeal was dismissed. The hyperglycaemic
state was caused by the disease of diabetes
itself and not an outside factor of injection of
insulin.

10. Burgess (1991)
• Mr Burgess attacked his friend. She had fallen
asleep when Burgess, allegedly sleepwalking, hit her
over the head with a bottle. He subsequently
picked up a video tape recorder and hit her on the
head with it. He put his hands around her throat,
and when she said, "I love you Bar," it appeared
that he came to his senses, and he called for an
ambulance.
• Held that defendant was not guilty by reason of
insanity. This case set the legal status of
committing violence while sleepwalking a form of
insanity.

11. External factors – Quick (1973)
• The appellant was a charge nurse in a hospital. He
attacked one of his patients whilst on duty. The
appellant sought to raise the defence of
automatism as at the time of the attack he was
hypoglycaemic, in that he had taken too much
insulin and eaten very little. In addition he had
consumed alcohol. The trial judge ruled that this
gave rise not to automatism but insanity. The
defendant then changed his plea to guilty and
appealed.
Held:
•
The appeal was allowed and the conviction was
quashed. His hypoglycaemia was caused not by his
diabetes but by the external factor of insulin.

12. Not knowing the nature and
quality of the act
• Defendant many not know the nature and
quality of his act if:
• 1)he is in a state of unconsciousness or
impaired consciousness
• 2)when he is conscious but due to his
mental condition he does not understand
nor know what he is doing.
• Windle, Johnson

13. Windle (1952)
• The appellant killed his wife. She was suicidal and
he administered an aspirin overdose. Medical
evidence supported the view that he was suffering
from a mental condition at the time of the crime.
On arrest he said to the police, "I suppose they will
hang me for this". The trial judge refused to allow
the defence of insanity to be put before the jury
as he had demonstrated that he realised that what
he was doing was unlawful.
Held:
•
The appeal was dismissed. The trial judge was
correct to refuse the defence of insanity.
Wrong, for the purposes of the M'Naghten
rules, meant unlawful. It did not matter that he
thought his actions were not morally wrong.

14. Johnson (2007)
• The defendant suffered from paranoid
schizophrenia and hallucinations, He
forced his way into his neighbours flat
and stabbed him.
• CA held that defence of insanity was
not available as D knew the nature and
quality of his acts and that they were
legally wrong.

15. Acronym
• Now using all of the cases think of an
acronym to help you remember them.
• You have 5 minutes.

16. Special Verdict
• When a defendant successfully proves
insanity the jury must return a verdict of
‘not guilty by reason of insanity’. Under the
Criminal Procedure (Insanity and Unfitness
to Plead) 1991 Act the judge can now
impose:
• 1) a hospital order
• 2) A supervision order
• 3) An absolute discharge

17. Problems with the law of
insanity?..
• The definition of insanity was set in 1843. At
this time medical knowledge was very limited,
It needs to be updated in light of modern
understanding of mental illnesses.
• Another problem is the definition is a legal
one-not medical!
• -So people who suffer from certain mental
disorders do not come into the definition, like
psychopaths. They know what they are doing is
wrong, but they cant prevent it
• -However those suffering from physical
disorders come into it, like sleep walking, even
if it is treatable.

18. The Overlap with Automatism
• Insanity overlaps with automatism-an act
done by the muscles without any control of
the mind. So its necessary to decide
whether the defendants automatic state is
due to a mental illness or external factors.
• This has extreme consequences as those
using the defence of automatism
successfully are entitled to a complete
acquittal. Whereas, on a finding of not
guilty by reason of insanity, the judge has
to impose some order on the defendant.

19. • It could be argued that the reason
courts are reluctant to al defendants to
use the full defence of automatism is
because it may lead to an acquittal and
defendants will be free from
supervisions or orders.

20. Proof
• The defendant has to prove that he is insane.
• The role of the jury is to decide if the
defendant is insane or not. So people with no
medical knowledge have to make a ‘medical
decision’.
• This means there's potential for jurors to be
confused by technical terminology.
• Also jurors might be so revolted by the crimes
they will refuse to return a verdict of not
guilty by reason of insanity.

21. Activity
• In Pairs, using your textbook, find the 3
proposals for reform that were made.

22. Proposals for Reform
• There are several proposals for reform on
the law on insanity.
• 1)In 1953, the Royal Commission on Capita;
Punishment suggested the M’Naghten Rules
should also cover where the defendant was
‘incapable of preventing himself from
committing the offence.
• -However instead the government
introduced the defence of diminished
responsibility.

23. • 2) The butler committee suggested the
verdict of not guilty by reason of
insanity should be replaced by verdict
of not guilty on evidence of mental
disorder.

24. • 3) In 1989 the Law Commission Drafts
Criminal Code proposed that a defendant
should be not guilty on evidence of severe
mental disorder/handicap.
• None of these proposals however have
been made law. However the way judges
can deal with defendants has improve, so
they can make supervision orders or
treatment orders.