What Is Voluntary Manslaughter?

In 2010, a street-based sex worker named Patricia Mary Butler was solicited by a client named Brendan Potter on the corner of Bourke and William street. 

After performing sexual acts on Mr Potter in Rushcutters Bay Park, both parties went to Butler’s apartment.

Once at the apartment, Mr Potter began to make vile comments to Ms Butler regarding performing sexual acts with children, and showed her child abuse material on his computer. 

He proceeded to ask Ms Butler to roleplay a fantasy of a stepfather abusing his daughter.

Ms Butler, having been the victim of sexual assault herself, snapped and beat Mr Potter to death with a piece of granite before slitting his throat.  

Despite intentionally killing Mr Potter, Ms Butler was subsequently convicted of voluntary manslaughter for her crime.

So, what is voluntary manslaughter? And how is it different from murder?

What is Manslaughter?

The offence of manslaughter is contained in under section 18 of the Crimes Act 1900 (NSW).

The offence relates to the unlawful killing of a person in circumstances which do not amount to murder. 

The maximum penalty for the offence is 25 year’s imprisonment.

Categories of manslaughter

There are two broad categories of manslaughter: involuntary manslaughter and voluntary manslaughter.

Involuntary manslaughter involves the unlawful killing of another person in the absence of the mens rea (or mental fault element) for the offence of murder. 

Voluntary manslaughter occurs when all of the elements of murder are present (including the mental fault element) but the culpability of the offender’s conduct is reduced due to the circumstances of the crime.

In New South Wales, there are three main doctrines underpinning voluntary manslaughter:

• Extreme provocation;
• Substantial impairment because of mental health impairment or cognitive impairment; and
• Excessive self-defence.

Extreme Provocation

The conviction of Patricia Mary Butler is an example of voluntary manslaughter on the basis of provocation, what is now known as “extreme provocation”.

Extreme provocation occurs when provocative conduct by the deceased prompts the accused to lose control and kill them. Examples can include if the deceased was attempting to sexually assault the accused, or if the deceased sexually assaulted the child of the accused.

Section 23(2) of the Act states that the partial defence of extreme provocation will occur if:

• The act of the accused that causes death was in response to conduct of the deceased towards or affecting the accused; 

• The conduct of the deceased was a serious indictable offence (punishable by 5 years imprisonment or more);
• The conduct of the deceased caused the accused to lose self-control; and
• The conduct of the deceased could have caused an ordinary person to lose self-control to the extent of intending to kill or inflict grievous bodily harm on the deceased.

Non-violent sexual advances by the deceased will not constitute grounds for extreme provocation. Nor will situations where the accused provokes the deceased’s conduct in order to have an excuse to use violence against them.

Substantial Impairment 

Section 23A of the Act provides a partial defence of substantial impairment because of mental health impairment or cognitive impairment. 

Unlike the defence of insanity, successful proof of substantial impairment would result in a conviction of manslaughter and not an acquittal.

Sections 23A(1) states that a partial defence of substantial impairment will be made out if:

• At the time of the acts or omissions causing the death, the person’s capacity to understand events, or to judge whether the person’s actions were right or wrong, or to control himself or herself, was substantially impaired by a mental health impairment or a cognitive impairment, and
• The impairment was so substantial as to warrant liability for murder being reduced to manslaughter.

A mental health impairment can include an anxiety disorder, an affective disorder, including clinical depression and bipolar disorder, a psychotic disorder and a substance-induced mental disorder that is not temporary.

A cognitive impairment can include an intellectual disability, borderline intellectual functioning, dementia, an acquired brain injury, drug or alcohol related brain damage, including foetal alcohol spectrum disorder and autism spectrum disorder.

In 2020, Matthew Flame was found guilty of manslaughter on the basis of substantial impairment after the killing of Liam Anderson, son of musician Angry Anderson. Flame bashed Anderson to death after the use of MDMA triggered a psychotic episode in which he believed Anderson was a demon. Flame was subsequently diagnosed with schizophrenia.

Excessive Self Defence

Section 421(1) outlines a partial defence of excessive self-defence where the accused believed their conduct was necessary to defend themselves or another person but the conduct is not a reasonable response in the circumstances as they perceive them.

Excessive self-defence is different from the full defence of self-defence as the accused actions were not a reasonable response. What counts as a “reasonable response” involves an objective assessment as to whether the accused actions were proportionate. 

For example, landing a punch in response to somebody threatening you with a knife would likely be seen as a reasonable response and therefore self-defence. However, if we reverse weapons, repeatedly stabbing a person who threatens you with a punch would likely amount to excessive self-defence.

In R v Stanley (No. 2) [2023] NSWSC 74, a young man pled guilty to manslaughter on the basis of excessive self-defence, after stabbing another man to death when the deceased and his friends showed up at the accused’s residence, after several threats were exchanged at a nearby party. Although the group of men did travel to the young man’s address to do him harm, they did not pose any immediate threat when the offender ran out of his house wielding a kitchen knife.