On 13 June 1966, the US Supreme Court delivered Miranda v Arizona 384 US 436 (1966).
The Court held that in order to protect the constitutional privilege against self incrimination under the 5th amendment of the US Constitution, an accused in custody must be informed of his or her right to remain silent; that anything he or she says may be used against him or her in court; and that he or she has the right to consult a lawyer who may present during any interrorgation.
The court held that the prosecution may not use statements of the accused whilst in custody unless the prosecution can show that they informed the accused of their right to silence and the right to a lawyer and that the accused understood this and voluntarily waved such rights in making such a statement.
Miranda warnings are typically phrased as follows:
“You have the right to remain silent. Anything you say can and will be used against you in a court of law. You have the right to an attorney. If you cannot afford an attorney, one will be provided for you. Do you understand the rights I have just read to you?”
The rule in Miranda v Arizona is specific to the United States and does not apply in Australia. There is no 5th amendment privilege against self-incrimination, though the High Court of Australia has held that under the Australian common law, no inference may be drawn from an accused’s silence: Petty & Maiden v R  HCA 34; (1991) 173 CLR 95 (5 September 1991).
See also: RPS v R  HCA 3; 199 CLR 620; 168 ALR 729; 74 ALJR 449 (3 February 2000).
However, if an accused choses to answer some questions but not others, inferences may be drawn against the questions the accused did not answer.
In limited circumstances, some questions must be answered, such as in traffic matters. One must give their name and address if they are to receive bail.
The NSW Evidence Act 1995 when first enacted said that no adverse inference could be drawn from the exercise of the right to silence by the accused. On 20 March 2013, the Act was amended so that the accused is cautioned with: “it may harm your defence if you fail to mention something now that you later rely on at trial”.
NSW law enforcement officers have traditionally given the following warning: “You are not obliged to say or do anything unless you wish to do so, but whatever you say or do may be used in evidence. Do you understand?”
Since the amendment of the Evidence Act, the NSW warning is: “You are not obliged to say or do anything unless you wish to do so. But it may harm your defence if you do not mention when questioned something you later rely on in court. Anything you do say and do may be given in evidence. Do you understand?”
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