Recent News

An In-Depth Look At General Defences In Criminal Law

Nov 17, 2023

Overview of General Defences

Defences in criminal law play an integral role in carrying out the function of criminal law. In Singapore, criminal law is mainly laid down through the Penal Code (“PC”), which encapsulates the codified law to protect the rights of individuals against harm. Notwithstanding, another important function of criminal law is to give a deserved response to culpable wrongdoing. To achieve as such, the law of defences seeks to ensure that offenders are given the avenue to reduce or rid themselves of liability, provided that the stringent requirements of the PC are satisfied. 

This article aims to provide a brief overview of certain general defences in criminal law, catering to the needs of criminal lawyers and the general public alike. General defences apply to all offences across the PC. Generally speaking, these defences can be categorised into justifications and excuses

In short, a person who invokes a justificatory defence claims his responsibility for the harmful conduct, but contends that this particular act was not blameworthy as it was done in circumstances which made the conduct rightful in the eyes of society.

Contrastingly, a person who invokes an excusatory defence concedes that his act itself was blameworthy, and accepts the harm caused by his conduct. However, he asserts that he cannot be held entirely liable for this blameworthy act due to the fallibility of human nature.

This article will examine in brief the justificatory defences of private defence and consent, and the excusatory defences of mistake, accident, duress, unsoundness of mind, and intoxication.

Justificatory Defences

Right of Private Defence

Private defence of person or of property is recognised by the Penal Code as a general defence which, if successfully pleaded, acquits the accused entirely of any offence.  

First, two preconditions must be fulfilled before the right of private defence may arise:

1. Per Section 97 of the PC, an offence affecting the human body or property was being committed against the accused or another person.

a. For persons, a threat or attempt to commit an offence will suffice.

b. For property, there must have been an attempt or offence committed against the accused.

2. Per Section 99(3) of the PC, there must have been no time or reasonable opportunity for the accused to seek recourse to public authorities for protection.

In addition to proving the preconditions under Sections 97 and 99(3) of the PC, the accused must prove a further three conditions before the defence will succeed. These can be categorised into:

1. The need for a reasonable apprehension of the danger;

2. The duration of the right of defence being commensurate with the continuation of the danger; and

3. The need for the force used to be necessary in defence.

Reasonable Apprehension of Danger

The law requires the accused to have reasonable apprehended the particular danger which he claims required him to exercise defensive action.

Regarding the defence of the person or property, Sections 101 and 104 provide respectively that the right of private defence even extends to the causing of death, as long as the accused reasonable apprehended a threat of death, grievous hurt, or that he would be unable to have recourse to the public authorities. 

Duration of the Right of Private Defence

The justificatory nature of this defence means that people are afforded this right only so long as the danger to their person or property continues. Once the danger has passed, the justification afforded by the law to commit what would otherwise be an offence, ceases to exist. In such situations, the accused should now seek recourse to public authorities and allow them to handle the situation accordingly. It follows that the law will regard any harmful response by the accused which occurs once the danger has ceased as unnecessary, and he will not be afforded the protection of this defence.

Use of Necessary Force

Per Section 98(1) of the PC, the right of private defence “does not extend to the inflicting of more harm than it is reasonably necessary in the circumstances”. Here, the word ‘necessary’ connotes an objective ascertainment of the force used by the accused to counter the danger. Nonetheless, the court will also consider the subjective circumstances of the accused to take into full account the danger that he apprehended.  


The defence of consent is laid down in Sections 87 to 92 of the Penal Code. If a successful defence is made out, it result in a complete acquittal of the crime charged.

Consent, or lack thereof, can determine criminal responsibility in two main ways:

1. First, where consent is necessary to the offence element, the prosecution must prove beyond a reasonable doubt the presence or lack of consent.

  • For example, where consent is made out in an allegation of rape, the offence element of rape would not be established.

2. Second, where the accused person claims that the alleged victim had consented to the suffering or hurt he or she experienced, the accused would thereby claim a defence of consent to rid himself of criminal responsibility.

In relation to the full defence of consent, a number of significant factors presuppose whether the defence is available. This includes:

  • The type of harm caused;
  • The age of the person consenting,
  • The consenting party’s ability to consent;
  • Whether a legal guardian can consent instead, and
  • Whether the harm had been done for the benefit of the consenting party.

Further, the full defence of consent is supplemented by Sections 90 and 91 of the PC, which respectively define consent in negative terms by stipulating when consent is not real, and declare when the defence of consent is unavailable to acts which constitute offences independently of any harm they might cause.

The justificatory nature of the defence of consent is seen especially in cases where the harm causing act was done for the benefit of the victim. Here, society approves of such an act where it was consented to by the victim, or performed in circumstances when it was impossible to obtain such consent.

Lastly, it is apposite to note that since the term ‘consent’ is not defined in the PC, it is open to the courts to interpret what constitutes consent, as long as this interpreted definition is in line with Section 90 of the PC. Generally, the definition given by the Kerala High Court is applied, where consent is defined as an “active will in the mind of a person to permit the doing of the act … and knowledge of what is to be done, or of the nature of the act that is being done”.

However, under Section 90 of the Penal Code, consent is vitiated where it was given by a person:

  • Under fear of injury or under a misconception of fact; or
  • Of unsound mind or intoxicated so as not to understand what he or she has consented to; or
  • Who was under 12 years of age unless the contrary appears from the context.

Excusatory Defences


Section 79 of the PC codifies the defence of mistake, which is premised on the fact that to err is human, and that people commit errors of judgements in their daily dealings. Notwithstanding the fact that such a defence exists, there is a necessarily high threshold to be reached before this defence can be invoked.

The defence of mistake does not negate the mens rea of the offence, in that one still wished to commit the illegal act, but instead seeks to provide for persons who act under the mistaken assumption that he was justified by law to commit the alleged criminal conduct. Accordingly, Section 26B of the PC provides that a mistake is made in good faith where the offender exercised due care and attention in the commission of the act.

Importantly, this defence stands only to exculpate offenders on the basis of a mistake as to a fact, as aforementioned, but not a mistake as to the law. This is because the law implies a duty onto every Singaporean resident to be acquainted with the knowledge of the law – such that citizens conduct themselves in a manner which conforms to the laws of the country. Therefore, persons who state they committed an offence due to their mistaken knowledge of the law will not be afforded protection under the defence of mistake.


Section 80 of the PC provides that “nothing is an offence which is done by accident or misfortune in the doing of a lawful act in a lawful manner, by lawful means, and with proper care and caution”.

Accordingly, there are two distinct parts to this defence. The first requires the offence to have been done by accident or misfortune, while the second part provides the rigorous conditions which the accused must satisfy before the defence will apply. This is to ensure that the accused was not blameworthy whatsoever when doing the act which resulted in the accident. Hence, the defence of accident operates as an excuse – although the accused’s conduct and its effect are wrongful, the law may exculpate the accused on account of the external circumstances comprising the accident.

Nonetheless, it must be noted that this defence has seldom been considered by the courts for various reasons. Most notably, most human conduct and their effects are done intentionally or knowingly, while accidents possess the inherent nature of being unintended and unknown.

Since the prosecution bears the burden of proving this element, the accused does not need to raise the defence of accident. Additionally, the requirements for proving the defence of accident form an extremely high threshold, which may prevent or dissuade an accused person from relying on it.


Section 94 of the PC provides for the defence of duress, which reads:

Except murder and offences against the State punishable with death, nothing is an offence which is done by a person who is compelled to do it by threats, which, at the time of doing it, reasonably cause the apprehension that instant death to that person or any other person will otherwise be the consequence:

Provided that the person doing the act did not of his own accord, or from a reasonable apprehension of harm to himself short of instant death, place himself in the situation by which he became subject to such constraint.”

Therefore, the defence of duress applies to rather narrow and unique set of circumstances, where the accused is required to have been threatened with instant death. This is far more onerous to prove than being threatened with impending harm, or serious injury. Further, this defence is unavailable to persons who permitted themselves to become involved in circumstances which exposed them to such threat. In addition, the courts require the accused to have taken a reasonable opportunity to escape if such an opportunity presented itself.

Nonetheless, these onerous requirements are present due to the excusatory nature of the defence – where the accused’s conduct is regarded as wrongful in society’s perspective, yet the law rules that the circumstances in which the accused found himself in render him blameless. It follows that a high threshold of extreme circumstances must be met, before the law and society will be prepared to excuse the accused for the wrong committed. It is also important to have these requirements in place to prevent against opening the floodgates to large numbers of individuals who wish to claim that they only committed an offence because they were threatened to do so. 

Accordingly, the rationale which underpins the defence of duress is that the accused must have been placed in extenuating circumstance where he was robbed of his free will as to whether or not to commit the crime in question.

Unsoundness of Mind

It is codified in Section 84 of the PC that the defence of unsoundness of mind can be entitled in instances where the offence is committed by an offender who is:

1. Incapable of knowing the nature of the act;

2. Incapable of knowing what he is doing is wrong;

3. Completely deprived of any power to control his actions.

The second provision applies only if the person is incapable of knowing that his act is “wrong by ordinary standards of reasonable and honest persons” and “wrong as contrary to law”.

This defence exists to acquit an offender on the basis that he does not possess the necessary fault element for the offence, since he was not of sound mind during the commission of the offence. Observing this from a criminal responsibility standpoint, where every person is a moral agent with the ability to exercise rational judgement, every person is thus responsible for the choice to engage in criminal activities. However, where the choice is as a result of mental impairment, that person cannot be held to be responsible for his acts, and the law would be unduly harsh to punish them as such.

Section 84 of the PC is read together with Sections 251 and 252 of the Criminal Procedure Code (“CPC”). This provides that individuals who are acquitted on the grounds of unsoundness of mind would be subject to any necessary treatment, and admitted to a mental asylum. This is to ensure both the protection of the public and the insane individual, as it is inappropriate for these individuals to be acquitted and released unconditionally into society. This is given the individuals’ mental impairment which is still present and uncured, thus resulting in the high potential for the individual to reoffend.


Section 85(2) of the PC provides that intoxication is only a defence to a criminal charge where, at the time of the offence:

a. The accused did not know what he was doing; or

b. The accused did not know that such act or omission was wrong.

Further, the state of intoxication must have been “caused without the knowledge or against the will of the person charged with the offence”. Under Section 85(2)(a), the accused must prove that he was involuntarily intoxicated against his consent by the malicious or negligent conduct of a third party. Additionally, the intoxication must have been so severe that the accused did not know that his actions were wrong, or that he did not know what he was doing. It is apposite to note that this provision is predicated on a third party’s malice or negligence in causing the accused’s intoxication.

For the defence under Section 86(2) to succeed, the surrounding circumstances must show that the accused was so intoxicated that he or she lacked the ability to form the intention or knowledge required for the offence. This assessment requires the credible and objective evidence of the accused’s level of intoxication.



Click one of our representatives below to chat on WhatsApp or email us at

× How can I help you?