1. Evaluation of Diminished Responsibility

2. Diminished Responsibility – Old Law
Original definition of diminished responsibility under S.2 Homicide Act 1957 (before it was updated by Coroners and Justice Act 2009) used vague terminology which did not fit with medical terminology:
“…suffering from an abnormality of mind (whether arising from a condition of arrested or retarded development of mind or any inherent causes 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”
There was also little guidance for juries as to when D’s mental responsibility was substantially impaired – gave a wide scope for juries to make their decision and led to arguments that the defence was becoming too easy to plead
But – the fact that the law was open to interpretation did allow a defence to women suffering from “battered women’s syndrome” and in mercy killing cases where D could argue they had become depressed living with a suicidal or terminally ill relative

3. Changes in the New Law
Changes arise from Coroners and Justice Act 2009
“Abnormality of mental functioning” replaces “abnormality of mind” – a term preferred by psychiatrists
From a recognised medical condition – reflects the need for modern terminology and proof of the defence to be based on medical diagnosis
“Substantial impairment” now more specific – mental abnormality must substantially impair D’s mental responsibility to understand the nature of his conduct, form a rational judgement, or exercise control
Also a causal link so D’s condition must provide an explanation for the killing

4. Evaluation
New defence deals with the criticisms of the old law and provides more clarity and modern terminology
But – likely to be interpreted narrowly and some deserving cases, e.g. mercy killings, may not be able to use the defence – people in these situations may be reacting to extremely stressful situations but may not have a recognised medical condition – vagueness of old law allowed for some flexibility but now there is a danger of some injustices
Overlap between diminished responsibility and insanity – insanity requires that D must be suffering from a disease of the mind that causes a defect of reason such that D does not know the nature and quality of his act. If D raises the defence of diminished responsibility, prosecution may argue for insanity so there is a special verdict where D is committed to a mental institution – could put Ds off pleading the partial defence to avoid a verdict of insanity

5. Suggested Reform
Law Commission suggested to include immaturity as part of the definition which would allow children a defence on the basis that there should be some consideration that if a 10 year old kills, there could be some issues with their maturity that could reduce murder to voluntary manslaughter
Government has not adopted this so there is a position where an adult who has the mental age of a child will be able to plead the defence but a child will not be able to because their immaturity is considered normal
Law Commission 2006 report suggests that voluntary manslaughter should be reclassified as “second degree murder” and still attract a discretionary life sentence as it does now. Reclassifying VM as murder would recognise the fact that the killing was intentional rather than accidental

6. Reclassification of Homicide – Law Commission Report 2006 – Proposals
First degree murder (mandatory life sentence):
Intentional killing; or
Killing with intent to cause serious injury, in the awareness there is a serious risk of causing death
Second degree murder (discretionary life sentence):
Killing with intent to do serious injury
Killing with intent to cause some injury or fear or risk of injury, in the awareness that there is a serious risk of causing death
Killing with the intent for first degree murder but where a defence of loss of control, diminished responsibility or suicide pact succeeds
Manslaughter (discretionary life sentence) – cover the different types of involuntary manslaughter that currently exists
Law Commission suggests that this three-tier structure of homicide would “give the jury in homicide trials greater power to reflect in their verdict the extent to which the offender was at fault in killing
No action has been taken on these proposals

7. Exam question on evaluation of fatal offences
Despite some recent reforms, there are still criticisms to be made of the current law on murder and voluntary manslaughter. Consider relevant criticisms of that law and consider any reforms that might be available
Outline relevant current law
Discuss strengths and weaknesses in law
Identify proposals for reform
Discuss how these proposals would improve the law