Legal Defences - NSW

1. Self-defence is a defence under section 418 of the Crimes Act 1900.
2. Self-defence is a complete defence (i.e. if it is established that you were acting in self-defence, you will not be held criminally responsible for the offence).
3. Self-defence is available for all offences except where death is inflicted to protect property or prevent trespass.

What must be established for it to be self-defence? 

For self-defence to apply when you are charged with a crime, the following must be the case: 

1. You believed that your conduct was necessary to eliminate a threat AND 
2. Your response to the threat was reasonable in the circumstances.

How can it be established that I believed my conduct was necessary for self-defence to be applicable?

There must be a reasonable possibility that you believed your conducted was necessary to either:

Defend yourself or another person OR

Prevent or stop your false imprisonment of the false imprisonment of another person OR

Protect property from damage or unlawful taking OR

Prevent or remove a person from trespassing on your land or premises.

What is a reasonable response in the circumstances?

This will be assessed objectively on a case-by-case basis. Conduct will be found to be reasonable if it was proportionate to the threat and not excessive.

Q: Is self-defence a complete or partial defence?

A: Self-defence is a complete defence. If you successfully raise this defence, you will not be held criminally responsible for your conduct provided the Prosecution does not disprove this defence beyond reasonable doubt.

Q: Is self-defence available for all offences?

A: You can raise this defence for most offences except where death is occasioned while protecting property or preventing trespass.

A person charged with a criminal offence may rely on the mental health impairment or cognitive impairment defence under the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW). 

If the defence is successfully established, the court may return a special verdict of “act proven but not criminally responsible.” This means the court accepts that the person committed the physical act, but finds they are not criminally responsible due to a mental health or cognitive impairment. 

To rely on this defence, it must be demonstrated that at the time of the alleged offence the person was experiencing a mental health impairment or cognitive impairment that caused a significant disturbance in their thought processes, mood, volition (decision-making), perception, or memory. 

This defence recognises that some individuals may not be criminally responsible for their actions where a serious mental health condition or cognitive impairment significantly affected their ability to understand or control their behaviour. 

1. Mental illness is a defence under the Mental Health (Forensic Provisions) Act 1990 (NSW).
2. Mental illness can be a complete defence (i.e. if you prove that you were mentally ill at the time of committing the offence, you will not be held criminally responsible for the offence).
3. The defence of mental illness is available for all offences.

For a defence of mental illness,

1. At the time of committing the offence, you had a defect of reason as a result of a disease of the mind AND
2. You did not have knowledge of the physical nature or quality of your actions AND
3. You did not know that what you did was considered morally wrong by the ordinary, reasonable person due to your defect.

What is a disease of the mind?

A disease of the mind refers to a state of mind which lacks ordinary reasoning capabilities due to a ‘disease, disorder or disturbance’. The disease may be temporary or permanent, curable or incurable (for example, schizophrenia is considered to be a disease of the mind).

What does ‘no knowledge of the physical nature or quality of the act’ mean?

This means that you may have been aware of your actions, but you were not aware of the outcome or the actual consequences of that action.

Q. Is the defence of mental illness a complete or partial defence?

A: Mental illness is a complete defence. If you successfully raise this defence, you will not be held criminally responsible for your conduct provided the Prosecution does not disprove this defence beyond reasonable doubt.

Q. Is the defence of mental illness available for all offences?

A: Yes, you can raise the defence of mental illness in all criminal proceedings.

Q: If I am severely under the influence of alcohol or drugs, can I use this defence?

A: No, mental malfunctioning due to the use of drugs or alcohol is not considered to be a disease of the mind.

In New South Wales, the honest and reasonable mistake of fact defence may apply to certain strict liability offences. 

This defence arises where an accused person held a genuine and honest belief about a set of facts which, if those facts had been true, would have made their conduct lawful. 

Importantly, the belief must not only have been honestly held by the accused, but it must also be objectively reasonable in the circumstances. In other words, the court must be satisfied that a reasonable person in the same situation could have held the same belief. 

If successfully established, the defence may result in the person not being found guilty of the offence. 

1. Honest and reasonable mistake of fact is a common law defence.
2. Honest and reasonable mistake of fact is a complete defence (i.e. if you discharge your evidentiary burden, you will not be held criminally responsible for the offence).
3. Honest and reasonable mistake of fact is usually available for strict liability offences.

1. You held a belief regarding a fact which was incorrect AND
2. You honestly held that belief AND
3. In the circumstances, it was reasonable to hold such a belief.

What is a strict liability offence?

Strict liability offences are offences where the Prosecutor is not required to prove that you had intended to commit the offence.

What does mistake of fact mean?

Mistake of fact does not include ignorance of the law. For example, if you are fishing in a protected area because you were informed that it was legal to fish there, that is a mistake of law and will not give rise to this defence. However, if you were fishing in area X which is a protected area but honestly and reasonably believed you were in area Y, then that is a mistake of fact that may give rise to this defence.

Q: Is honest and reasonable mistake of fact a complete or partial defence?

A: Honest and reasonable mistake of fact is a complete defence. If you successfully raise this defence, you will not be held criminally responsible for your conduct provided the Prosecution does not disprove this defence beyond reasonable doubt.

Q: Is the defence of honest and reasonable mistake of fact available for all offences?

A: This defence is usually raised in matters involving strict liability offences (i.e. where the Prosecution is not required to prove that you had intended to commit the alleged offence).

In New South Wales, substantial impairment by abnormality of mind is a partial defence to murder. If successfully established, it reduces a charge of murder to manslaughter. 

To rely on this defence, it must be shown that at the time of the alleged offence the accused was suffering from an underlying condition that was not temporary, and that this condition substantially impaired their ability to understand events, judge whether their actions were right or wrong, or control their behaviour. 

The impairment must be significant enough to reduce the person’s level of criminal responsibility, meaning a conviction for manslaughter rather than murder may be appropriate. 

1. Substantial impairment by abnormality of the mind is a defence under section 23A of the Crimes Act.
2. Substantial impairment by abnormality of the mind is a partial defence (i.e. if the elements of this defence are satisfied, the offence you are to be convicted of will be downgraded, for example, you will be convicted of manslaughter instead of murder).
3. Substantial impairment by abnormality of the mind is only available for the offence of murder.

At the time of offending, your capacity to:

1. understand events OR
2. judge whether your actions were right or wrong OR
3. control yourself
4. was substantially impaired by an abnormality of the mind which arises from an underlying medical condition AND
5. the impairment was so substantial to warrant a reduction in liability.

What is abnormality of the mind?

Abnormality of the mind is an objective assessment. You may be considered to have an abnormal mind if your state of mind is not similar to that of an ordinary mind and is likely to be considered abnormal by a reasonable person. The abnormality of the mind need not be absolute but more than trivial.

What is an underlying medical issue?

An underlying medical issue refers to a pre-existing mental or physiological condition (for example, PTSD).

Q: Is substantial impairment by abnormality of the mind a complete or partial defence?

A: Substantial impairment by abnormality of the mind is a partial defence. If you successfully raise this defence, you will still be convicted, but you will be convicted of a lesser offence (i.e. manslaughter instead of murder).

Q: Is substantial impairment by abnormality of the mind available for all offences?

A: No, substantial impairment by abnormality of the mind is only available for a charge of murder.

1. Extreme provocation is a defence under section 23 of the Crimes Act.
2. Extreme provocation is a partial defence (i.e. if the elements of this defence are satisfied, the offence you are to be convicted of will be downgraded, for example, you will be convicted of manslaughter instead of murder).
3. Extreme provocation is only available for the offence of murder.

1. The deceased engaged in provocative conduct AND
2. That conduct caused you to lose self-control AND
3. It was reasonable in the circumstances for you to lack self-control.

What is provocative conduct?

The conduct of the deceased will be considered to be provocative if what they engaged in constitutes a serious indictable offence (i.e. an offence that is punishable by 5 years imprisonment or more).

What is meant by reasonable in the circumstances to lose self-control? 

This is an objective assessment of whether the ‘ordinary person’ in your position would have lost self-control to such an extent that they would have intended to kill or cause grievous bodily harm.

Q: Is extreme provocation a complete or partial defence?

A: Extreme provocation is a partial defence. If you successfully raise this defence, you will still be convicted, but you will be convicted of a lesser offence (i.e. manslaughter instead of murder).

Q: Is extreme provocation available for all offences?

A: No, extreme provocation is only available for a charge of murder.

In New South Wales, the defence of claim of right may apply for offences involving the taking of property (whether physical or intangible). Claim of right acts as a defence in circumstances where a person takes a property tin a way that would normally amount of an offence but at the time they honestly believed they had a proprietary or possessory (i.e.) legal right to the property, even if that belief is mistaken.  

Offences where a claim of right may arise include:

1. Theft
2. Robbery
3. Aggravated robbery
4. Deceptively obtain financial advantage

1. Claim of right is a common law defence 
2. Claim of right is a complete defence.

In order to successfully raise a claim of right the following must apply:

1. The claim of right must be one that involves a belief as to the right to the property or money in the hands of another. 
2. The claim must be genuinely, that is, honestly held — whether it was well founded in fact or law or not. 
3. While the belief does not have to be reasonable, a colourable pretence is insufficient (that is, you must actually believe you have a legal right to a property, not just a belief that you might have a right). 
4. The belief must be one of a legal entitlement to the property and not simply a moral entitlement. 
5. The existence of such a claim, when genuinely held, may constitute an answer to a crime in which the means used to take the property involved an assault, or the use of arms — the relevant issue being whether the accused had a genuine belief in a legal right to the property rather than a belief in a legal right to employ the means in question to recover it. 
6. The claim of right is not confined to the specific property or banknotes which were once held by the claimant, but can also extend to cases where what is taken is their equivalent in value, although that may be qualified when, for example, the property is taken ostensibly under a claim of right to hold them by way of safekeeping, or as security for a loan, yet the actual intention was to sell them. 
7. The claim of right must extend to the entirety of the property or money taken. Such a claim does not provide any answer where the property or money taken intentionally goes beyond that to which the bona fide claim attaches. 
8. The claim of right must extend to the entirety of the property or money taken. Such a claim does not provide any answer where the property or money taken intentionally goes beyond that to which the bona fide claim attaches. 
9. It is for the Crown to negative a claim of right where it is sufficiently raised on the evidence, to the satisfaction of the jury.