Voluntary Manslaughter - Diminished Responsibility AO1

What is diminished responsibility?

• Diminished responsibility is a partial defence to murder.

  Section 2 (1) of the Homicide Act 1957 as amended by section 52 of the Coroners and Justice Act 2009 states:

A defendant who kills or is a party to the killing is not to be convicted of murder if:

• The defendant was suffering from an abnormality of mental functioning which -

• arose from a recognised medical condition,

• substantially impaired the defendant’s ability,

• provides an explanation for the defendant’s acts or omissions in doing or being a party to the killing.

What is an abnormality of mental functioning ?

• An abnormality of mental functioning is where the defendant’s mental functioning is so different from that of an ordinary human being that the reasonable person would deem it necessary to be abnormal.

What is the R v Byrne (1960) case ?

Facts: The defendant was a sexual psychopath who strangled his victim and then mutilated her body. He claimed that he was unable to control his perverted sexual desires.

Held: The court of appeal held that the term “ abnormality of mind” Covered all aspects of the mind, including the ability to control physical acts as well as the ability to make rational decisions. Byrne’s conviction was reduced to manslaughter.

What is a recognised medical condition ?

• The abnormality of mental functioning must be caused by a recognised medical condition.

What is diminished responsibility and intoxication ?

• If the defendant is voluntarily intoxicated, alone this cannot provide the defence diminished responsibility. Voluntary intoxication is not capable of forming an abnormality of functioning.

• If the defendant has a pre-existing abnormality of mental functioning and then becomes a voluntarily intoxicated, the defence of diminished responsibility can be successful if they abnormal mental functioning is the cause of the killing.

• Alcohol Dependency Syndrome is a recognised medical condition (R v Tandy).

What is the R v Tandy (1989) case ?

Facts: The defendant was an alcoholic who strangled her 11-year-old daughter.

Held: The defendant admitted to having some control of her cravings as her first drink was voluntary, she was not able to rely on the defence.

What does it mean to be substantially impaired ?

Section 1 (b) states the abnormality of mental functioning must substantially impair the defendants ability to:

• Understand the nature of their conduct

• Form a rational judgement

• Exercise self-control

In R v Lloyd it was decided that ‘the impairment did not be total, but it must be more than trivial or minimal’

What does provide an explanation mean ?

Section 1B states that the abnormality of mental functioning must provide an explanation for the defendant’s acts and omissions in doing or being a party to the killing (R v Dietschmann).

What is the case of R v Dietschmann ?

Facts: The defendant had been in a relationship with his aunt and suffered from depression when she died. After drinking heavily, the defendant attacked his victim as he believed the victim had broken his watch a gift from his dead aunt.

Held: It was up to the jury to decide whether despite the drink his mental abnormalities substantially impaired his mental responsibility for his actions.

What is the outcome ?

• If diminished responsibility is successful, the defendant will not be guilty of murder and will be guilty of voluntary manslaughter, this allows the judge discretion when it comes to sentencing.