Diminished Responsibility- new law

Diminished Responsibility
ALL will be able to identify where the defence of
diminished responsibility comes from
MOST will be able to explain the effect of a
successful plea of diminished responsibility
SOME will be able to explain the law in relation
to diminished responsibility
What is voluntary manslaughter?
• Voluntary Manslaughter is where the Defendant has
committed murder, but raises a special (partial) defence
which justifies a lesser sentence (and avoids mandatory
• D is not acquitted if successful in raising this defence.
• The judge can issue any sentence they feel appropriate (up
to life imprisonment)
• There are only one of three circumstances where D can
raise a special defence:
– Diminished Responsibility
– Loss of Control
– Suicide Pact (not studied in the course)
• It is a special defence because it can only be used where D
is charged with murder.
a. What is voluntary manslaughter?
b. What is the effect of a successful plea of
voluntary manslaughter?
c. What three circumstances may a defendant
use for voluntary manslaugter?
d. What is a special defence?
Diminished Responsibility
• Introduced by Homicide Act 1957 and amended by
Coroners and Justice Act 2009– previously if a person
with mental problems killed, only defence insanity.
• Definition is set out in S2 Homicide Act 1957 as amended
by S52 Coroners & Justice Act 2009 and requires the
defendant to prove (on a balance of probabilities):
1. D was suffering from abnormality of mental functioning
2. Which is due to recognised medical condition
3. Which substantially impairs D’s ability to understand
nature of conduct OR form rational judgment OR
exercise self control
4. The abnormality provides explanation for D causing V’s
death : causal link between medical condition & killing
a. Where does the authority for diminished
responsibility come from?
b. Who has to prove the defence?
c. What standard does this burden have to be
proven by?
d. What 4 things must be proven for diminished
responsibility to be successful?
What is Abnormality of Mental
• objective view of what is ‘abnormal’: reasonable man’s view
• TEST for abnormality of mental functioning: ‘state of mind so
different from that of ordinary people that the reasonable
person would term it abnormal’ – R v Byrne [1960]. Although
this case uses the old test, it’s likely the courts will use this
a. What does ‘abnormality of mental
functioning’ mean? Use case authority!
Cause of abnormality of mental
• Such inability must be due to a recognised medical condition
• Does not have to be permanent, but must exist at time of killing
• Case examples pre-amended defence:
• psychopath: R v Byrne (1960)
• depression: R v Seers (1984)
• Battered Woman Syndrome: R v Ahluwalia (1992)
• NB: Can be induced by disease or injury BUT NOT INTOXICATION, UNLESS
reached state where Brain has been injured – drinking involuntary – R v
Tandy (1989) CA
• However, CA recently shown more sympathy for D’s who kill while
suffering from ADS: alcohol dependence Syndrome : R v Wood [2003] –
no longer prove brain damage – up to jury to decide if alcoholism
substantially impaired D’s ability … & that D’s alcohol consumption
directly resulted from ADS.
NB: There must be medical evidence at the trial to prove abnormality of
mental functioning.
Task 4
a. What must cause the abnormality of mental
b. Give some examples of abnormality of mental
c. What evidence must be provided in order to
prove this?
d. Using the case of Stewart (James) (2009) explain
the guidelines for diminished Responsibility and
alcohol dependency syndrome.
Abnormality must substantially impair D’s acts
or omissions
• i.e. D must not be able to understand the
consequences of his actions/find it difficult to
rationalise/have self control due to his
abnormality of the mind.
• To what degree (must be substantial) is a Q for
the jury to decide: Lloyd (1967) – does not
mean total, nor does it mean minimal;
something in between.
What must be substantially impaired?
D must do 1 of 3 things in order for the jury to
consider him to be substantially impaired:
• D must not be able to understand nature of
conduct – includes situations where D doesn’t
know what he is doing e.g. automatic state.
• OR form rational judgment (whether act is
right or wrong)
• OR exercise self control – e.g. Byrne (was
unable to control perverted desires)
Task 5
a. The abnormality of mental functioning must
substantially impair D’s acts or omissions.
What three ways may D be substantially
b. What does ‘substantial impairment’ mean?
The abnormality must provide an
explanation for D’s conduct
CONTRIBUTING FACTOR in causing D to carry
out his conduct which killed V?
• E.g. Is there a causal link between the medical
condition & the killing?
• NB: Abnormality of the mind need not be the
only factor that caused D to be involved in the
killing but it must be the significant factor.
Abnormality of mental functioning
and intoxication
• Was D intoxicated at the time of the killing? If so, D’s
abnormality of mental functioning must be a significant
factor in causing the victims death. It is irrelevant if he
was intoxicated: (Dietschmann).
• NB: Drinking/taking drugs is not a medical condition
even if it has an effect on the brain unless it creates a
recognised abnormality of mental functioning: Di Duca
• However where D suffering from alcoholism (and the
alcoholism was a significant factor in causing V’s death)
this would be considered an abnormality of mental
functioning: Wood (2008)
How has the law been reformed?
• Defence recently updated to deal with many of
the previous problems identified by the Law
Commission report Murder, Manslaughter and
Infanticide (2006):
• Allows for developments in medical science by
allowing the phrase ‘recognised medical
• The new act also sets out what must be
substantially impaired whereas the old one
didn’t. i.e. D must not be able to understand the
nature of his conduct; to form a rational
judgement or exercise self control.
Diminished responsibility under s52 CJA 2009
Evaluation of this change – the following differences apply:
• Whereas previously there needed to be an abnormality
of the mind there now needs to be an abnormality of
mental functioning
• Whereas previously the abnormality needed to have
substantially impaired his mental responsibility for his
actions now this needs to have substantially impaired
the D’s ability to either understand the nature of his
conduct, to form a rational judgment or to exercise
self-control and this provides an explanation in respect
of the killing
Are there any problems that still exist?
• Yes!
• Nearly every other defence raised by D has to be
disproved by the Pros. For DR D raises but has to prove
it. This conflicts with article 6 ECHR (innocent until
proven guilty).
• This can also be difficult for jurors to understand as
many D’s will run two defences at once and will have
different burdens for the jury to consider.
• Medical evidence shows that the frontal lobes of the
brain (responsible for self-control) do not develop until
14, which conflicts with the age of criminal
responsibility as developmental maturity is not the
same as a learning disability and may not fall within the
‘recognised medical condition’ criteria for mental
What is the effect of a successful plea of
diminished responsibility?
What are the current problems with the law on
diminished responsibility?
Who does the burden rest with?
By what standard does the burden have
to be proven?
If D is intoxicated at the time of the killing,
what must be proven (refer to legal
What is the test for abnormality of
mental functioning? Byrne (1960_
Causation needs to be satisfied. What
needs to be established for this to be
Definition comes from?
What 4 things must be proven ?
as amended
What evidence needs to be obtained in order
for mental functioning to be proven?
What does substantially impair
mean refer to authority?
What one of three things would constitute
substantial impairment? Where D doesn’t…
Give some examples of what would constitute abnormality
of mental functioning with supporting authority.
Does the abnormality of mental
functioning need to be permanent?
Whether D is substantially
impaired is a question for
who to decide?

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