Criminal Law
TP1 Notes
,Week 5 – Diminished Responsibility [Lecture 5]
The defence of DR recognises that it is less culpable to kill when the mind is
disturbed than it is to kill when the mind is operating normally. The essence of this
defence is that some form of transient disruption to the defendant’s mental state has
rendered them less blameworthy than would otherwise be the case.
- It is a SPECIAL DEFENCE to murder in that it is purely a defence to murder
only, would result if successfully achieved, in being found guilty of Voluntary
Manslaughter as opposed to Murder.
Acts/Developments for the law:
• Created by s2(1) Homicide Act 1957
• Amended by s52 Coroners and Justice Act 2009
Old Laws:
• The old law under s.2 of the Homicide Act 1957 provided for conviction of
manslaughter only where at the relevant time, the offender was
• suffering from “such abnormality of mind (whether arising from a condition of
arrested or retarded development of mind or inherent cause or induced by
disease or injury) as
• substantially impaired his mental responsibility for his acts and omissions in
doing or being party to the killing”.
Requirements to establish DR:
Section 2 (1): D at the time of killing is suffering from an abnormality of mental
functioning, which:
(a) Arose from a recognised medical condition (s.2(1)(a) HA 1957)
(b) Substantially impaired D’s ability to
i. Understand the nature of his conduct (s.2(1A) HA 1957)
ii. Form rational judgements (s.2(1A) HA 1957)
iii. Exercise self-control (s.2(1A) HA 1957)
(c) Provides an explanation for D’s acts and omissions in being party to or doing the
killing (see s.2(1B) HA 1957)
CASE LAW: Consider R v Challen (2019).
Consider R v Blackman (2017) and R V Hussain (2019)
Pleas of guilty on the grounds of DR should only be accepted where there was ‘clear
evidence’ of mental imbalance.
The plea was refused in the following cases.
• Din (1962)
• Walton (1978)
In Byrne 1960, Lord Parker CJ described it as ‘ a state of mind so different from that
of ordinary human the reasonable man would term it abnormal’.
, DR (abnormality of mental functioning) v Insanity (disease of the
mind) –
• Insanity is very narrow in scope- defendant did not know what he was doing
or that he did not know that it was wrong
• DR encompasses all aspects of the mind’s activities and not just the
defendant’s brain. DR does not require a defendant to be insane or partially
insane. DR is much wider than insanity
• Thus, a defendant may plead DR even though:
-he appreciated what he was doing in killing the victim, and
-knew that it was wrong
Diminished Responsibility v Insanity:
• Insanity – special verdict “not guilty by reason of insanity”. Acquittal inevitably
leads to committal to a mental institution for an indeterminate length of time
• Diminished Responsibility –Statistics reveal that 50% of those convicted for
manslaughter due to DR receive hospital orders under s37 Mental Health Act
1983. Of the remainder sentences tend to range from probation and
suspended sentences to various terms of imprisonment.
Diminished responsibility requirements:
1) Abnormality of mental functioning
2) It must arise from a recognised medical condition
3) Defendant must prove that his abnormality of mental functioning (arising from
a recognised medical condition) substantially impaired his:
• “ability to understand the nature of his/her conduct”
• and/or “form a rational judgment”
• and/or “exercise self-control”
4) The abnormality must provide an ‘explanation’ for D’s act’s and omissions in
doing or being a party to the killing
- Abnormality must be a significant contributory factor in causing the
defendant to kill
FURTHER CASES:
As established under R v. Bryne (1960) - It is for the jury to decide what substantially
impaired is.
In R v Brown 2011 – the Court of Appeal confirmed the phrase- thus the abnormality
had to be more than a minimal or trivial contribution to the killing, but it did not need
to be the sole cause of the killing
R v Golds 2016 - ‘Substantial’ means ‘significant or appreciable’. Therefore,
something which is ‘more than minimal or trivial’ is insufficient to be significant.
Also (See R v Conroy (2017))
SEE MORE ON POWERPOINT 5 / LECTURE 5
TP1 Notes
,Week 5 – Diminished Responsibility [Lecture 5]
The defence of DR recognises that it is less culpable to kill when the mind is
disturbed than it is to kill when the mind is operating normally. The essence of this
defence is that some form of transient disruption to the defendant’s mental state has
rendered them less blameworthy than would otherwise be the case.
- It is a SPECIAL DEFENCE to murder in that it is purely a defence to murder
only, would result if successfully achieved, in being found guilty of Voluntary
Manslaughter as opposed to Murder.
Acts/Developments for the law:
• Created by s2(1) Homicide Act 1957
• Amended by s52 Coroners and Justice Act 2009
Old Laws:
• The old law under s.2 of the Homicide Act 1957 provided for conviction of
manslaughter only where at the relevant time, the offender was
• suffering from “such abnormality of mind (whether arising from a condition of
arrested or retarded development of mind or inherent cause or induced by
disease or injury) as
• substantially impaired his mental responsibility for his acts and omissions in
doing or being party to the killing”.
Requirements to establish DR:
Section 2 (1): D at the time of killing is suffering from an abnormality of mental
functioning, which:
(a) Arose from a recognised medical condition (s.2(1)(a) HA 1957)
(b) Substantially impaired D’s ability to
i. Understand the nature of his conduct (s.2(1A) HA 1957)
ii. Form rational judgements (s.2(1A) HA 1957)
iii. Exercise self-control (s.2(1A) HA 1957)
(c) Provides an explanation for D’s acts and omissions in being party to or doing the
killing (see s.2(1B) HA 1957)
CASE LAW: Consider R v Challen (2019).
Consider R v Blackman (2017) and R V Hussain (2019)
Pleas of guilty on the grounds of DR should only be accepted where there was ‘clear
evidence’ of mental imbalance.
The plea was refused in the following cases.
• Din (1962)
• Walton (1978)
In Byrne 1960, Lord Parker CJ described it as ‘ a state of mind so different from that
of ordinary human the reasonable man would term it abnormal’.
, DR (abnormality of mental functioning) v Insanity (disease of the
mind) –
• Insanity is very narrow in scope- defendant did not know what he was doing
or that he did not know that it was wrong
• DR encompasses all aspects of the mind’s activities and not just the
defendant’s brain. DR does not require a defendant to be insane or partially
insane. DR is much wider than insanity
• Thus, a defendant may plead DR even though:
-he appreciated what he was doing in killing the victim, and
-knew that it was wrong
Diminished Responsibility v Insanity:
• Insanity – special verdict “not guilty by reason of insanity”. Acquittal inevitably
leads to committal to a mental institution for an indeterminate length of time
• Diminished Responsibility –Statistics reveal that 50% of those convicted for
manslaughter due to DR receive hospital orders under s37 Mental Health Act
1983. Of the remainder sentences tend to range from probation and
suspended sentences to various terms of imprisonment.
Diminished responsibility requirements:
1) Abnormality of mental functioning
2) It must arise from a recognised medical condition
3) Defendant must prove that his abnormality of mental functioning (arising from
a recognised medical condition) substantially impaired his:
• “ability to understand the nature of his/her conduct”
• and/or “form a rational judgment”
• and/or “exercise self-control”
4) The abnormality must provide an ‘explanation’ for D’s act’s and omissions in
doing or being a party to the killing
- Abnormality must be a significant contributory factor in causing the
defendant to kill
FURTHER CASES:
As established under R v. Bryne (1960) - It is for the jury to decide what substantially
impaired is.
In R v Brown 2011 – the Court of Appeal confirmed the phrase- thus the abnormality
had to be more than a minimal or trivial contribution to the killing, but it did not need
to be the sole cause of the killing
R v Golds 2016 - ‘Substantial’ means ‘significant or appreciable’. Therefore,
something which is ‘more than minimal or trivial’ is insufficient to be significant.
Also (See R v Conroy (2017))
SEE MORE ON POWERPOINT 5 / LECTURE 5
