27 / 3 / 2023


‘Entrapment’ is not considered a legal defence under Australian law but can, in rare circumstances, lead to the exclusion of evidence at trial if it was done in an unlawful or improper manner.

The legal concept of ‘entrapment’ is generally understood by most. By way of example:

  • An undercover police officer approaches a person and asks the person to supply drugs to them
  • The person supplies drugs to the undercover police officer
  • The undercover police officer arrests the person and charges them with supplying drugs
  • The person is, however, not guilty of that offence because they were ‘entrapped’ by the police officer

In the United States, the defence of entrapment arises in circumstances where, immediately before committing the offence, the defendant had no intention of committing the offence and only commits the offence because the “deception [of a police officer] actually implants the criminal design in the mind of the defendant”. It is not enough for the police officer to merely provide opportunities or facilities for the defendant to commit the offence; the defendant must be truly induced into committing the offence.

Under Australian law, however, there is no “defence” of entrapment. It is recognised by courts (see the High Court matter of Ridgeway v The Queen (1995) 184 CLR 19) that in some circumstances deception is the only technique available for law enforcement officers to detect crime. A prime example of this is undercover officers adopting fake identities online to detect drug trafficking or child sex offences. The mere fact that a defendant has been tricked into committing an offence does not provide a defence to a criminal charge.

There can be some protection against this type of behaviour by police officers in particular circumstances. While not operating as a defence, it may be that the evidence which would otherwise be used to prove the offence is not admitted into evidence. Section 138 of the Evidence Act holds:

(1)     Evidence that was obtained—

(a)     improperly or in contravention of an Australian law; or

(b)     in consequence of an impropriety or of a contravention of an Australian law;

must not be admitted unless the desirability of admitting the evidence outweighs the undesirability of admitting evidence that has been obtained in the way in which the evidence was obtained.

In practical terms, this means that if a police officer uses improper or unlawful means to obtain a piece of evidence, a court may exclude that evidence and it will not form part of the case against the defendant. To use our example above, the drugs given to our undercover officer would be the key piece of evidence to prove that the drugs had actually been supplied by the defendant. If the physical drugs, or evidence relating to the drugs, were excluded from evidence, it is very unlikely that the charge would be able to be proved.

The court must balance the importance of the evidence against the seriousness of the impropriety however. If the evidence is highly important and discloses a serious criminal offence, and meanwhile the impropriety by the police officer is relatively minor, the evidence is likely to be admitted.

Courts may be more inclined to consider exclude evidence obtained as a consequence of entrapment if police either did not have proper authority to engage in a lawful “controlled operation” or if they did not have reasonable grounds to suspect a defendant was already engaging in the same type of criminal activity before they were induced by police into committing an offence.

While there is no defence of entrapment at law in Australia, it is similarly by no means a free-for-all whereby police officers can use any methods available to investigate offences and obtain evidence. It is a balancing exercise with fairness at its core.

Thomas Tiffen, Lawyer