Criminal Law – Lecture 22-20-19
Partial Defences to Murder
Sometimes, where D kills V with the requisite actus reus and mens rea for murder, legally
recognized forms of extenuation exist via so-called ‘partial defences’ to murder.
Where successfully raised, these defences reduce what would otherwise be a conviction for
murder to a conviction for ‘voluntary’ manslaughter (and expose D to the more flexible
sentencing regime of manslaughter).
We will look at two of these partial defences:
1. Diminished Responsibility.
2. Loss of Control.
Context:
- only defences to murder (not defences to attempted murder).
- Both DR/LoC were reformed by the Coroners and Justice Act 2009 (prior to reform LoC was
known as ‘Provocation’; the name for DR is unchanged). The new versions of these defences
came into force on 4 October 2010.
- We will not be considering the old law on these defences (although a few old cases may be
used to help understand the new law).
- Partial defences circumvent the mandatory life sentence for murder.
1. Diminished Responsibility
Structure of the Revised Defence:
This defence was previously outlined in s. 2(1) Homicide Act 1957 (HA). A much vaguer
version which could be pragmatically manipulated to accommodate defendants who would
not usually qualify for DR – but whose cases engendered sympathy in trying to avoid a
murder conviction and sentence (eg. mercy killers).
2(1): A person (“D”) who kills or is a party to the killing of another is not to be
convicted of murder if D was suffering from an abnormality of mental functioning
which –
(a) arose from a recognized medical condition,
(b) substantially impaired D’s ability to do one or more [emphasis
added] of the things mentioned in subsection (1A), and
, (c) provides an explanation for D’s acts and omissions in doing or
being party to the killing.
* M. Gibson, ‘Pragmatism Preserved? The Challenges of Accommodating Mercy Killers in
the Reformed Diminished Responsibility Plea’ (2017) 81 Journal of Criminal Law 177.
(Amends s. 2(1) Homicide Act 1957 (HA). And instates S. 52 Coroners and Justice Act 2009
amends s. 2(1) HA and in its place substitutes a new version of s. 2(1) HA 1957 along with
ss. 2(1A) – 2(1B) HA 1957)
Expert Witnesses:
On a practical level the role of psychiatrists, doctors and psychologists should be noted, either
at trial or for getting the prosecutions plea accepted before trial. Experts are there to give
evidence on the tests for diminished responsibility but they shouldn’t at the end really offer
an overall opinion on whether D satisfies the defence, that is the role of the jury.
At trail where expert evidence is uncontradicted and unchallenged the jury must accept it.
But where experts disagree the jury may still come to its own outcome.
Burden Standard of Proof for the Defence:
[WITHIN THE BOUNDS OF PROBABILTY] – only applicable in diminished responsibility and
insanity.
In most criminal defences the defendant has an evidential burden Meaning that the defence
has to raise evidence for the defence. Eg:
- Self defence
- Provocation
- Insanity
(1B): For the purposes of section 2(1)(c), an abnormality of mental functioning provides
an explanation for D’s conduct if it causes, or is a significant contributory factor in
causing, D to carry out that conduct.
2(2): On a charge of murder it shall be for the defence to prove that the person charged is
by virtue of this section not liable to be convicted of murder.
The Legal Tests for Diminished Responsibility
Partial Defences to Murder
Sometimes, where D kills V with the requisite actus reus and mens rea for murder, legally
recognized forms of extenuation exist via so-called ‘partial defences’ to murder.
Where successfully raised, these defences reduce what would otherwise be a conviction for
murder to a conviction for ‘voluntary’ manslaughter (and expose D to the more flexible
sentencing regime of manslaughter).
We will look at two of these partial defences:
1. Diminished Responsibility.
2. Loss of Control.
Context:
- only defences to murder (not defences to attempted murder).
- Both DR/LoC were reformed by the Coroners and Justice Act 2009 (prior to reform LoC was
known as ‘Provocation’; the name for DR is unchanged). The new versions of these defences
came into force on 4 October 2010.
- We will not be considering the old law on these defences (although a few old cases may be
used to help understand the new law).
- Partial defences circumvent the mandatory life sentence for murder.
1. Diminished Responsibility
Structure of the Revised Defence:
This defence was previously outlined in s. 2(1) Homicide Act 1957 (HA). A much vaguer
version which could be pragmatically manipulated to accommodate defendants who would
not usually qualify for DR – but whose cases engendered sympathy in trying to avoid a
murder conviction and sentence (eg. mercy killers).
2(1): A person (“D”) who kills or is a party to the killing of another is not to be
convicted of murder if D was suffering from an abnormality of mental functioning
which –
(a) arose from a recognized medical condition,
(b) substantially impaired D’s ability to do one or more [emphasis
added] of the things mentioned in subsection (1A), and
, (c) provides an explanation for D’s acts and omissions in doing or
being party to the killing.
* M. Gibson, ‘Pragmatism Preserved? The Challenges of Accommodating Mercy Killers in
the Reformed Diminished Responsibility Plea’ (2017) 81 Journal of Criminal Law 177.
(Amends s. 2(1) Homicide Act 1957 (HA). And instates S. 52 Coroners and Justice Act 2009
amends s. 2(1) HA and in its place substitutes a new version of s. 2(1) HA 1957 along with
ss. 2(1A) – 2(1B) HA 1957)
Expert Witnesses:
On a practical level the role of psychiatrists, doctors and psychologists should be noted, either
at trial or for getting the prosecutions plea accepted before trial. Experts are there to give
evidence on the tests for diminished responsibility but they shouldn’t at the end really offer
an overall opinion on whether D satisfies the defence, that is the role of the jury.
At trail where expert evidence is uncontradicted and unchallenged the jury must accept it.
But where experts disagree the jury may still come to its own outcome.
Burden Standard of Proof for the Defence:
[WITHIN THE BOUNDS OF PROBABILTY] – only applicable in diminished responsibility and
insanity.
In most criminal defences the defendant has an evidential burden Meaning that the defence
has to raise evidence for the defence. Eg:
- Self defence
- Provocation
- Insanity
(1B): For the purposes of section 2(1)(c), an abnormality of mental functioning provides
an explanation for D’s conduct if it causes, or is a significant contributory factor in
causing, D to carry out that conduct.
2(2): On a charge of murder it shall be for the defence to prove that the person charged is
by virtue of this section not liable to be convicted of murder.
The Legal Tests for Diminished Responsibility
