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What Are the Key Defences to Murder and Manslaughter? 

The primary difference between murder and manslaughter is the element of intention.

Murder and manslaughter are two of the most serious charges in the Australian justice system, and both carry long sentences for offenders.

If you have been charged with murder or manslaughter, there are a variety of legal defences which may be available to you. Due to the seriousness of these charges, you should consult expert legal advice immediately in order to give yourself the best chance of mounting a
successful defence and avoiding a lengthy term of imprisonment.

Here, we discuss the differences between murder and manslaughter, as well as potential legal defences to murder and manslaughter charges.

What is the Difference Between Murder and Manslaughter?

Murder and manslaughter are both homicide charges, which means that they involve one person killing another.

In Queensland, homicide is dealt with under the Criminal Code 1899 (Qld), which states that any person who commits homicide is guilty of a crime which can fall into one of two categories: murder or manslaughter.

Murder is defined under the code as the unlawful killing of another person with intent to kill or cause grievous bodily harm, if death is caused by act or omission with reckless indifference to human life or if death is caused by an act done in the prosecution of an unlawful purpose.

Manslaughter is defined as the unlawful killing of a person under such circumstances that do not amount to murder, often resulting from a reckless, negligent or careless act.

The primary difference between murder and manslaughter is the element of intention. In the majority of murder cases, the prosecution must prove that the defendant intended to kill their victim, whereas this is not the case in a manslaughter trial where the killing was unintentional.

If a person is convicted of murder in Queensland, the punishment is mandatory life imprisonment, which cannot be mitigated.

Manslaughter has a maximum penalty of life imprisonment under the Criminal Code, but unlike murder, mitigating factors regarding the offence can be taken into consideration by the Judge during sentencing in a manslaughter case. The penalty of life imprisonment is not
mandatory, which means that judges have discretion in deciding what sentence to impose based on the circumstances surrounding the manslaughter.

What Are Some Legal Defences to Murder Charges?

If you have been charged with murder, there are a variety of defences to murder which your legal team may employ.

These defences are either full defences, which result in the complete exoneration of the accused if successful, or partial defences, which may reduce a murder charge to a manslaughter charge and result in lower sentences.

Common defences to murder include:


In Queensland, the law permits a person to use reasonable force to physically defend themselves, another person or their property. Self-defence is a full defence, which means that if you have been charged with murder and can demonstrate that the homicide was in fact committed in self-defence, you will be acquitted of the murder charge.

The degree of force used in self-defence must be proportionate to the perceived danger, meaning that unless there was a reasonable threat of death or grievous bodily harm to the accused, the amount of force used in self-defence must not have been likely to have resulted in death or serious harm.

Once self-defence has been raised as a defence, the prosecution will have to convince the jury beyond a reasonable doubt that your actions should not be considered reasonable self-defence.


An insanity defence is a full defence set out in section 27(1) of the Criminal Code 1899. It applies if at the time of committing the offence the accused was suffering some form of mental disease or infirmity which made them unable to understand or control their actions, or
unable to determine that they should not have acted as they did.

In Queensland, every person is presumed sane until the contrary is proven. This means that the defendant must show that they were of unsound mind at the time of the offence. The Mental Health Court will decide whether a person was of unsound mind when the offence
was committed, as well as whether they are fit to stand trial.

The Criminal Code also notes that “The provisions of section 27 apply to the case of a person whose mind is disordered by intoxication or stupefaction caused without intention on his or her part by drugs or intoxicating liquor or by any other means.”

This means that if you were involuntarily intoxicated at the time of the offence, you may be able to claim insanity. However, if you were voluntarily intoxicated at the time of the offence, you cannot claim insanity.

Diminished Responsibility

Diminished responsibility is a partial defence to murder and can be used to downgrade a murder charge to a manslaughter charge.

Described in section 304A of the Criminal Code 1899, this defence is applicable in cases when a person who has unlawfully killed another person was at the time of the act, “in such a state of abnormality of mind (whether arising from a condition of arrested or retarded
development of mind or inherent causes or induced by disease or injury) as substantially to impair the person’s capacity to understand what the person is doing, or the person’s capacity to control the person’s actions, or the person’s capacity to know that the person
ought not to do the act or make the omission.”

The degree of mental disorder required for a diminished responsibility defence is less than that of an insanity defence.

It is worth noting that voluntary intoxication does not count as creating diminished responsibility.


Have You Been Charged with Murder or Manslaughter?

If you have been charged with murder or manslaughter, you are facing a life-changing legal battle which requires expert legal advice.

At Guest Lawyers, our team has extensive experience defending those charged with murder and manslaughter, and will be able to assist you in creating an effective defence strategy.

We offer initial consultations (including in prisons) to assist with murder or manslaughter charges, and act for all persons required to appear before the Magistrates and Supreme Court. We also conduct appeals in the Court of Appeal and High Court.

We have a lawyer on call 24 hours per day, who is always ready to provide you with relevant and important advice. Please get in touch to speak to one of our team members and discuss how we can help.