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Overview of Criminal Law Defences: Honest & Reasonable Mistake, Self Defence, Claim of Right & Duress

If you are facing criminal charges our Criminal Lawyers Sydney & NSW can help you to successfully defend a matter by either convincing the police to withdraw the matter by pointing out deficiencies in the prosecution’s case or applying a legal defence if the matter proceeds to court.

As you are likely aware, the burden of proof lies with the prosecution. Because our experienced Criminal Lawyers know what the police are required to do to prove each offence, we may be able to have the matter withdrawn or convince the Court that there is no case to answer and have it dismissed. Examples of this include if the police have acted outside their guidelines and rules or if evidence crucial to the police case is unavailable on the day.

Alternatively, the police may present a strong case and it may be possible to apply a legal defence to your case. Such a legal defence can be a partial defence which can persuade the Court to reduce the penalties you are likely to receive, or a complete defence which may justify your actions and negate the need for punishment.

Below you will find a list of the more frequently used legal defences. Our criminal lawyers are available to discuss any of these defences with you, or perhaps another defence not mentioned here, and can be contacted on 02 9521 2222. You can also send your enquiry online now and we will call you shortly.

Honest and reasonable Mistake

Although not strictly a ‘legal defence’, honest and reasonable mistake is often mistakenly considered a defence and it is perhaps helpful if it is considered with the other defences. It can be applied if it can be established that a defendant had an honest and reasonable mistaken belief of fact which led to the defendant taking the action for which they have been charged. If this can be shown, then the defendant’s actions may be considered innocent and a serious sentence may not be applied. If this is the case, the technical reason is because the prosecution has failed to prove the elements of their case and not because of a legal defence.

Self defence

Self defence is a complete defence and if successful, the accused will be acquitted of the charge. Self defence is defined by Part 11 Division 3 of the Crimes Act 1900 (NSW) which states:

A person carries out conduct in self-defence if and only if the person believes the conduct is necessary:

(a)   to defend himself or herself or another person, or

(b) to prevent or terminate the unlawful deprivation of his or her liberty or the liberty of another person, or

(c)   to protect property from unlawful taking, destruction, damage or interference, or

(d) to prevent criminal trespass to any land or premises or to remove a person committing any such criminal trespass

and the conduct is a reasonable response in the circumstances as he or she perceives them

It is important to note the last line, “a reasonable response in the circumstances as he or she perceives them”, which imports both subjective and objective considerations when assessing this defence.

Claim of Right

This defence can be used to defend charges which contain the element of larceny, including theft and stolen property matters. If the accused person believes that they are entitled to the property in question then that belief is a defence to any crime involving larceny. The belief must be a genuine belief and it is the accused person’s responsibility to prove that they did have a genuine belief that they are entitled to the property in question.

This defence can be extended to apply when the accused person holds a genuine belief that the property belongs to another person and they acquired the property on behalf of that other person.


Duress is a complete defence and if successful, the accused will be acquitted of the charge. The burden of proof rests with the accused. This defence is available it can be established:

(a)    the accused acted in response to a threat of physical harm that will be carried out unless the offence is committed;

(b)    there was no reasonable way to render the threat ineffective; and

(c)     the action taken by the accused was a reasonable response to the threat.

Essentially, it must be shown that the accused had no real choice and the actions taken by the accused, which caused the offence, were simply a response to the threat made.

If you have been charged with a criminal offence, call one of our criminal defence lawyers on (02) 9521 2222. Alternatively you can send your enquiry online now and one of our criminal lawyers will call you shortly.


A member of our legal team will contact you as soon as possible