Introduction

Voluntary manslaughter is a category of unlawful homicide. It can apply in cases where a defendant who would otherwise be guilty of murder is able to plead one of two specific partial defences.

The partial defences, diminished responsibility and loss of control, can be found in the Coroners and Justice Act 2009. If a defendant successfully pleads one of these defences he may be found guilty of manslaughter not murder. A manslaughter verdict allows the judge more discretion in sentencing.

Definition

The defence of diminished responsibility was originally introduced by the Homicide Act 1957. It extended the narrow defence of insanity to allow for those suffering a wider range of mental health issues to have a partial defence to unlawful killing.

The burden of proof lies with the defence to prove, on the balance of probabilities, that the requirements for diminished responsibility can be applied to the defendant’s situation.

Abnormality of mental functioning

Abnormality of mental functioning replaces the term abnormality of mind , used in the Homicide Act 1957.

It is likely that the courts will continue to apply the same standard of abnormality. So the test will be whether the defendant’s mental functioning was so different from that of ordinary human beings that the reasonable man would term it abnormal.

Recognised medical condition

The term recognised medical condition is broad enough to cover both physical and psychological conditions.

There must be medical evidence presented at trial to confirm an abnormality of mental function caused by a recognised medical condition.

Substantially impaired

A defendant’s abnormal mental functioning must substantially impair his mental responsibility for his acts or omissions in doing or being a party to the killing.

The phrase is unchanged from the Homicide Act 1957 so old case law is relevant.

The substantial impairment must be in relation to one of three aspects of the defendant’s mental responsibility: understanding the nature of his conduct, forming a rational judgement or exercising self control.

• Understand the nature of his conduct

Covers situations where a defendant is acting automatically and is not aware of his conduct.

This can include people suffering delusions or those with severe learning difficulties which means there mental age is so low they do not know what they are doing.

• Form a rational judgment

Applies if the defendant does know the nature of his conduct but cannot form a rational judgement about his acts or omissions.

Defendant’s suffering from paranoia or schizophrenia may not be able to form rational judgements.

Martin [2002]

Defendant shot intruders at his home, one died and the other was seriously injured.

Defendant was found to be suffering from a longstanding paranoid personality disorder. It was recognised as a medical condition which substantially impaired his ability to form a judgement for the purpose of diminished responsibility.

• Exercise self-control

  If the defendant has a recognised medical condition which prevents him from exercising self control.

  Byrne (1960)

  Defendant was a sexual psychopath. It was found that his condition substantially impaired his ability to exercise control over his perverted desires so the defence of diminished responsibility was available to him.

Provides an explanation

It must be proved that the substantial impairment to the defendant’s mental responsibility, caused by a recognised medical, provides an explanation for his conduct.

This causal connection was introduced in the Coroners and Justice Act 2009. The abnormality of mental functioning does not need to be the only factor which caused the defendant to act as he did but must be a substantial one.

Intoxication

Diminished responsibility becomes more complex if the defendant was intoxicated at the time of the killing.

• General rule

  Intoxication cannot support a defence of diminished responsibility.

  Di Duca (1959)

  Court of Appeal held the immediate effects of alcohol or drugs were not sufficient to amount to an injury (medical condition). Although there may be an effect on the brain, it was transient and was not an abnormality of mental functioning.

  The wording of the Coroners and Justice Act 2009 strengthens this view as it requires the abnormality of mental functioning to be caused by a recognised medical condition. Effectively, limiting jury discretion to find diminished responsibility.

• Pre existing abnormality of mental functioning

  Further complications occur where the defendant suffers some abnormality of mental functioning and is also intoxicated when he commits the unlawful killing.

  Dietschmann (2003)

  Defendant violently kicked and punched the victim to death. Defendant accused the victim of damaging a watch given to him by his deceased aunt.

  Psychiatrists suggested the defendant was suffering from an adjustment disorder, a depression caused by grief. Defendant had also been drinking heavily.

  Lord Hutton: Assuming that the defence have established that the defendant was suffering from mental abnormality... the important question is: did that abnormality substantially impair his mental responsibility for his acts in doing the killing? You know that before he carried out the killing the defendant had had a lot to drink. Drink cannot be taken into account as something which contributed to his mental abnormality and to any impairment of mental responsibility arising from that abnormality. But you may take the view that both the defendant's mental abnormality and drink played a part in impairing his mental responsibility for the killing and that he might not have killed if he had not taken drink. If you take that view, then the question for you to decide is this: has the defendant satisfied you that, despite the drink, his mental abnormality substantially impaired his mental responsibility for his fatal acts, or has he failed to satisfy you of that? If he has satisfied you of that, you will find him not guilty of murder but you may find him guilty of manslaughter. If he has not satisfied you of that, the defence of diminished responsibility is not available to him... .

  If the defendant can satisfy the jury that his abnormality of mind (mental functioning) substantially impaired his mental reasoning at the time of the killing then the jury should find him guilty of manslaughter not murder. The fact he was intoxicated may not be relevant.

  Hendy (2006)

  Defendant stabbed and killed a complete stranger. Defendant was intoxicated but there was evidence he had brain damage and a psychopathic disorder.

  Court of Appeal overturned murder conviction and substituted for manslaughter.

  Robson (2006)

  Defendant was heavily intoxicated but was also suffering from an acute stress disorder at the time of the killing.

  Court of Appeal quashed the conviction for murder in favour of manslaughter.

  This case law is likely to be followed under the Coroners and Justice Act 2009.

• Addiction and dependency

  Alcohol Dependence Syndrome (ADS) is a recognised medical condition and a sufferer cannot control their drinking.

  Tandy (1989)

  Defendant strangled her 11 year old daughter . Defendant was an alcoholic who had drunk nearly a whole bottle of vodka before the killing.

  Defendant’s conviction for murder was upheld because the evidence showed that she had exercised control over her drinking that day.

  Lord Watkins: If the alcoholism has reached the level at which her brain had been injured by the repeated insult from intoxicants so that there was gross impairment of her judgment and emotional responses, then the defence of diminished responsibility was available to her ... if her drinking was involuntary, then her abnormality of the mind at the time of the act of strangulation was induced by her condition of alcoholism... .

  The decision has been criticised as it only considered whether the defendant was unable to prevent themselves drinking and not whether alcoholism is a disease.

  Wood (2008)

  Defendant had been heavily drinking and killed the victim in a frenzied attack using a meat cleaver. At the trial, experts agreed defendant had alcohol dependency syndrome but disagreed whether this damaged his brain.

  The jury were directed that diminished responsibility was available as a defence if they found the defendant to have suffered brain damage as a result of drinking or if the defendant’s drinking was involuntary. Otherwise the defence was not available to the defendant. Defendant was convicted of murder.

  Court of Appeal quashed the conviction on the basis the judge was wrong to direct the jury that the defendant’s drinking had to be entirely involuntary.

  Court of Appeal: In our judgment Dietschmann requires a re-assessment of the way in which Tandy is applied in the context of alcohol dependency syndrome where observable brain damage has not occurred. The sharp effect of the distinction drawn in Tandy between cases where brain damage has occurred as a result of alcohol dependency syndrome and those where it has not, is no longer appropriate... .

  Stewart (2009)

  Defendant had been sleeping rough and became involved in an argument with the victim. Defendant admitted killing the victim when heavily intoxicated. Defendant suffered from alcohol dependency syndrome and argued this made his drinking involuntary and caused brain damage. Defendant was convicted of murder.

  Court of Appeal overturned the conviction on the basis of a misleading jury instruction, as in Wood (2008).

  Court set out three stages for a jury to consider in such cases:
  .. first, whether the defendant was indeed suffering from an abnormality of mind at the time of the killing... it does not necessarily follow from the fact that the defendant suffers from alcohol dependency syndrome that he has established the necessary abnormality of mind... depends on the jury's findings about the nature and extent of the syndrome and whether, looking at the matter broadly, his consumption of alcohol before the killing is fairly to be regarded as the involuntary result of an irresistible craving for or compulsion to drink...
  .. the second question, is whether this was caused by disease or illness...
  .. finally... whether the defendant's mental responsibility for what he did was substantially impaired should be addressed in conventional terms.. .

  Although the case law relates to the Homicide Act 1957 it is likely a similar approach will be taken under the Coroners and Justice Act 2009 .

  Therefore, in such cases, a jury must consider whether a defendant was suffering from an abnormality of mental functioning. If so, was this caused by alcohol dependency syndrome? If so, did this mean the defendant’s mental responsibility was substantially impaired? Also, the jury must decide whether the abnormality caused or was a significant factor in causing the defendant to kill the victim.