General Defences to Crime (VCE SSCE Legal Studies): Revision Notes
General Defences to Crime
Introduction to criminal defences
When studying criminal offences in Australian Legal Studies, it is important to understand that an accused person can raise defences to contest criminal charges. Criminal offences are classified into two main categories: indictable offences (serious crimes heard in the County Court or Supreme Court before a judge and jury) and summary offences (minor crimes heard in the Magistrates' Court before a magistrate).
A defence to a crime is a justification or lawful reason given by an accused person to explain why they should not be found guilty of a criminal offence. If successfully argued, a defence can lead to the accused being acquitted (found not guilty) or being convicted of a lesser offence instead.
Defences fall into two distinct categories:
- General defences can be used to contest various criminal charges. For example, self-defence can apply to crimes such as murder, manslaughter, and assault (though not to offences like theft)
- Specific defences only apply to particular offences. For example, the defence of "right of claim" (where someone honestly believes they own property) applies only to property offences such as theft
This note examines the seven main general defences available in Victorian criminal law: self-defence, mental impairment, duress, sudden or extraordinary emergency, automatism, intoxication, and accident.
Defence 1: Self-defence
Self-defence is one of the most commonly raised general defences in criminal law. An accused person can use this defence when they have taken action to protect themselves or others from harm.
Requirements for self-defence
For self-defence to succeed, the accused must demonstrate that they:
- Believed their actions were necessary to protect or defend themselves (or others)
- Perceived their actions to be a reasonable response in the circumstances
The key aspect of self-defence is that it focuses on the accused's subjective belief about the threat they faced and whether their response was objectively reasonable given those circumstances.
Burden of proof in self-defence cases
Once the accused raises self-defence by presenting evidence suggesting a reasonable possibility they acted in self-defence, the burden of proof shifts to the prosecution. The prosecution must then prove, beyond reasonable doubt, that the accused did not act in self-defence.
The burden of proof refers to the obligation or responsibility of a party to prove a case. In criminal cases, this burden usually rests with the prosecution, who must prove the accused's guilt beyond reasonable doubt.
Case example: Police officer's claims of self-defence
Case Study: Police Officer Self-Defence Claim (2017)
In a 2017 case, a police officer was charged with unlawfully assaulting a man in custody at Moe police station. The incident was captured on CCTV footage, which showed the detained man kicking out at the officer from a bench in his cell, striking the officer's thigh. The officer responded by dragging the man to the ground and punching him multiple times in the head.
The Defence Argument: The officer claimed he acted in self-defence and that the man had also spat at him, though this could not be confirmed by CCTV footage or witnesses.
The Outcome: A magistrate found the officer guilty and placed him on a 12-month good behaviour bond. The officer appealed to the County Court, arguing self-defence.
The County Court Decision: The County Court upheld the conviction, finding the evidence against the officer "overwhelming". The judge noted that "it was [the victim] who appeared to perceive the need for self-defence" rather than the accused officer.
Key Learning: This case demonstrates that self-defence must be proportionate and genuinely necessary based on the circumstances.
Exam tip: When analysing self-defence, always consider whether the force used was proportionate to the threat faced and whether the accused genuinely believed protection was necessary.
Defence 2: Mental impairment
Mental impairment is a condition of the mind that impacts a person's ability to know the nature and quality of their conduct, or to understand that the conduct was wrong. This defence recognizes that some individuals, due to mental illness, cannot form the necessary criminal intent (mens rea) to be held fully responsible for their actions.
Requirements for mental impairment
An accused may use the defence of mental impairment if, at the time of the offence, they were suffering from a mental illness and, as a result, they:
- Did not know what they were doing because they had little understanding of the nature and quality of their actions, and
- Did not know their conduct was wrong or could not reason or think about their conduct like an ordinary person
Both elements must be satisfied for the defence to succeed.
Presumption of sanity and burden of proof
An important feature of mental impairment is that an accused is presumed to be sane unless proven otherwise. This creates an exception to the usual rule about burden of proof in criminal cases.
Mental impairment can be raised by either the prosecution or the defence at any time during a trial. However, the burden of proving the existence of mental impairment falls on the party who raises it. In most cases, the accused raises this defence, meaning the burden of proof is reversed and the accused must prove mental impairment existed.
Special verdict and secure treatment orders
When mental impairment is successfully argued, it does not result in immediate release. Instead of an ordinary "not guilty" verdict, the court returns a special verdict of "not guilty by reason of mental impairment".
Following this special verdict, the court may impose a secure treatment order, which requires the offender to be compulsorily detained and receive treatment at a mental health service, such as a forensic mental health hospital. This ensures the person receives appropriate care while protecting public safety.
Exam tip: Remember the key difference: mental impairment relates to the accused's mental state at the time of the offence, not at the time of trial (which would be "unfit to stand trial").
Defence 3: Duress
Duress involves strong mental pressure on someone to overcome their independent will and force them to do something. This defence acknowledges that people may commit crimes when subjected to serious threats of harm.
Requirements for duress
An accused may use duress as a defence to any criminal offence if, at the time of the offence, they had a reasonable belief that:
- A threat of harm existed
- The threat would have been carried out unless the offence was committed
- Committing the offence was the only reasonable way to avoid the threatened harm, and
- Their conduct was a reasonable response to the threat
A reasonable belief is an honestly held opinion about circumstances which would seem to another ordinary person with similar characteristics (such as age or maturity), and in similar circumstances, to be sensible or correct.
Duress and family violence
In cases involving family violence, evidence of ongoing family violence may be relevant in determining whether an accused acted under duress. For example, if a person who has been a victim of family violence intentionally caused injury to their partner, believing this was the only reasonable way to avoid threatened harm, evidence of the history of family violence may support their claim of duress.
This recognizes that victims of family violence often face ongoing threats and coercive control that may affect their assessment of available options.
Burden of proof for duress
Once the defence raises the issue of duress by presenting evidence suggesting a reasonable possibility the accused acted under duress, the prosecution holds the burden of proving, beyond reasonable doubt, that the accused did not act under duress.
Exam tip: When evaluating duress, consider whether alternative courses of action were available and whether the response was proportionate to the threat.
Defence 4: Sudden or extraordinary emergency
This defence applies when an accused commits a crime while responding to an unexpected emergency situation. It recognizes that people may need to take unlawful actions to deal with urgent circumstances.
Requirements for sudden or extraordinary emergency
An accused may use this defence to any criminal offence if, at the time of the offence, they had a reasonable belief that:
- There was a sudden or extraordinary emergency
- Their actions were the only reasonable way of dealing with the situation, and
- Their actions were a reasonable response to the situation
Common Emergency Scenarios:
Examples of sudden or extraordinary emergencies might include natural disasters such as floods, fires, or earthquakes. For instance:
- A person might take someone else's boat (technically theft) to escape rising floodwaters
- Someone might break into a building (trespass) to shelter from a bushfire
In both cases, the unlawful action is justified by the genuine emergency circumstances where no reasonable alternative was available.
Burden of proof
Once an accused raises the defence of sudden or extraordinary emergency by presenting evidence suggesting a reasonable possibility their action arose due to such circumstances, the burden of proof falls on the prosecution to prove, beyond reasonable doubt, that the accused did not act in response to a sudden or extraordinary emergency.
Exam tip: This defence requires genuine emergency circumstances where no reasonable alternative was available. The response must be proportionate to the emergency faced.
Defence 5: Automatism
Automatism is a rare but significant defence. It refers to a state in which a person has a total loss of control over their bodily movements (is not conscious or aware of what they are doing), meaning they cannot form an intention to commit a crime (mens rea).
When automatism may apply
The defence of automatism may be raised in cases where an accused commits an offence:
- While sleeping or sleepwalking
- While suffering from concussion
- During an epileptic seizure
- As a result of a medical condition or due to a side effect of the proper use of medication
The crucial element is that the accused had no voluntary control over their actions and was not conscious of what they were doing.
Difficulty in proving automatism
Automatism is extremely rare and difficult to prove. Expert medical evidence is typically required to establish that the accused was genuinely in an automatic state at the time of the offence.
While the burden of proof varies according to the cause of the automatism, generally the prosecution must prove, beyond reasonable doubt, that the accused acted voluntarily (was aware of their actions when committing the offence).
Case example: Police officer found not guilty due to automatism
Case Study: Automatism Following High-Speed Chase (NSW)
In a rare successful case, a police officer in New South Wales was found not guilty of assault by reason of automatism.
The Incident: The officer had been involved in a high-speed car chase that ended in a near-fatal crash. After the collision, video footage showed the officer assaulting the other driver by kicking, punching, and stomping on him.
The Defence Evidence: The accused officer had no memory of the assault or the 10 minutes following the incident. He argued he was experiencing automatism at the time. Expert evidence was presented by both sides:
- The prosecution's expert could not rule out that the accused was experiencing "sane automatism"
- The defence relied on expert reports suggesting the officer was suffering from post-traumatic amnesia at the time of the assault and was therefore in an automatic state
The Outcome: The officer was found not guilty due to automatism.
Key Learning: This case illustrates how rare and difficult automatism is to prove, requiring substantial expert medical evidence.
Exam tip: Automatism requires complete loss of voluntary control. Reduced control or impaired judgment is not sufficient for this defence.
Defence 6: Intoxication
Intoxication as a defence applies when an accused acted involuntarily or without intent due to being intoxicated from consuming alcohol, taking drugs, or ingesting another substance. However, this defence has important limitations.
Key limitation: Non-self-induced intoxication
Under the Crimes Act 1958 (Vic), to successfully argue intoxication as a defence, the accused must prove that their state of intoxication was not self-induced. This is a crucial restriction that prevents people from using voluntary intoxication as an excuse for criminal behaviour.
The accused can demonstrate non-self-induced intoxication by proving their intoxication was:
- Involuntary (they did not choose to consume the substance)
- Due to fraud (they were deceived about what they were consuming)
- Due to a reasonable mistake (they genuinely but mistakenly believed they were consuming something else)
- Due to force (they were compelled to consume the substance)
- Due to the effects of proper use of prescription or non-prescription medication
For example, if someone's drink was spiked without their knowledge, or if they experienced an unexpected adverse reaction to properly taken medication, they may be able to argue intoxication as a defence.
Exam tip: Self-induced intoxication is generally not a defence. The law does not allow people to escape criminal responsibility simply because they chose to become intoxicated.
Defence 7: Accident
The defence of accident addresses situations where an accused's criminal actions were genuinely unintentional. As examined in earlier studies, most criminal offences require both a physical act (actus reus) and a guilty mind or intention (mens rea). The prosecution must prove, beyond reasonable doubt, that the accused's actions were deliberate and intentional.
When accident applies as a defence
The accused may raise the defence that their actions were an accident if the actions they took to commit the offence were:
- Involuntary (not under their conscious control)
- Unintentional (not what they meant to do)
- Reasonably unforeseeable by an ordinary person (could not have been anticipated)
For example, if someone accidentally knocked over a display in a shop, causing damage, they might raise accident as a defence to criminal damage charges. The key is that they did not intend to cause the damage and it was not reasonably foreseeable.
Exception: Strict liability offences
It is important to note that the defence of accident does not apply to strict liability offences. Strict liability offences do not require proof of mens rea (guilty mind), meaning the prosecution only needs to prove the physical act occurred, regardless of the accused's intention or state of mind.
Exam tip: When evaluating accident as a defence, consider whether the accused had any intention to commit the act and whether the outcome was reasonably foreseeable.
Unfit to stand trial
In addition to defences to crime, there is an important procedural safeguard that prevents trials from proceeding when an accused person cannot properly participate in the legal process.
What unfit to stand trial means
A person may be considered unfit to stand trial if they are unable to undertake essential tasks at the time of their trial, including being unable to:
- Understand the nature of the charges laid against them
- Enter a plea (say whether they are guilty or not guilty)
- Follow the course of the trial (understand what is happening)
- Instruct their lawyer (communicate with and provide information to their legal representative)
Difference from mental impairment
Being unfit to stand trial is fundamentally different from the defence of mental impairment:
- Unfit to stand trial refers to the accused's condition at the time of the trial
- Mental impairment (as a defence) refers to the accused's condition when they committed the offence
It is possible for someone to be fit to stand trial but raise mental impairment as a defence, or to be unfit to stand trial but not have a mental impairment defence available.
Process for determining fitness to stand trial
In Victoria, when there is a valid question about whether an accused is fit to stand trial, an investigation is held before the court. A jury determines, on the balance of probabilities (meaning more likely than not), whether the accused is unfit to stand trial.
Case example: Multiple accused found unfit to stand trial
Case Study: Three People Found Unfit to Stand Trial in Murder Case
In three separate Supreme Court jury trials, three people (referred to as Person A, Person B, and Person C) were found unfit to stand trial in relation to the alleged murder of a 36-year-old deaf man who fell 12 metres to his death from an apartment balcony in Ringwood, Melbourne.
Person A: Person A was found unfit to stand trial based on multiple factors:
- His IQ was only 59, placing him in the bottom 0.3% of intellectual ability among adults
- He had suffered a brain injury from a brain tumour at age seven
- He had been profoundly deaf since age two
- Two forensic psychologists testified that Person A did not understand the court's process, could not give proper instructions to his lawyers, could not follow the trial, and suffered from significant memory issues
Person B:
- Had borderline intellectual ability
- Was born deaf and suffered from a developmental disorder
- Did not have a normal understanding of the world around her
- Two experts concluded she was unable to understand the nature of the charge or trial and would not be able to follow proceedings
- She was deemed unfit to stand trial
Person C:
- Had an IQ of 61, placing him in the intellectually disabled range
- Required assistance from two Auslan (Australian Sign Language) interpreters
- However, one interpreter did not believe Person C understood Auslan sufficiently to comprehend the proceedings
- Both the prosecution and defence agreed it was not appropriate for Person C to stand trial
Key Learning: These cases illustrate how severe cognitive impairments, communication difficulties, or developmental disabilities can render someone unable to participate meaningfully in their own trial, making it unfair to proceed with criminal prosecution.
Exam tip: When discussing unfitness to stand trial, focus on the accused's ability to participate in the trial process, not their mental state at the time of the alleged offence.
Remember!
Key Concepts to Remember:
- General defences can be used for multiple criminal offences, while specific defences apply only to particular crimes
- The burden of proof usually lies with the prosecution to disprove a defence once it is raised (except for mental impairment, where the accused typically must prove it)
- Self-defence requires the accused believed their actions were necessary and perceived them as reasonable in the circumstances
- Mental impairment relates to the accused's mental state when committing the offence and results in a special verdict with possible secure treatment
- Duress applies when someone commits a crime under threat of harm, with no reasonable alternative
- Automatism is rare and difficult to prove, requiring complete loss of voluntary control over bodily movements
- Intoxication is only a defence if it was not self-induced
- Unfit to stand trial is different from mental impairment—it concerns the accused's ability to participate in the trial, not their mental state during the offence
Exam Technique:
When evaluating defences in exam questions, always consider:
- Whether the specific elements of the defence are satisfied
- Who bears the burden of proof
- Whether the defence is appropriate for the type of offence charged
Use the "BELIEVE and PERCEIVE" approach for self-defence, "THREAT must be REAL" for duress, and always distinguish between conditions at the time of the offence versus at the time of trial.