General principles in criminal law

Contributed by Bill de Mars and Judith Fordham and current to 1 September 2005

Important principles of the criminal law are as follows:

INNOCENT UNTIL PROVEN GUILTY

The basis of our system of criminal justice is that a person is to be considered innocent, even though he or she has been charged with an offence, until he or she is proved guilty of that offence.

BURDEN OF PROOF IS ON THE PROSECUTION

The task of proving the guilt of an accused is for the prosecution and it is not up to the person charged to establish his or her innocence. A person charged is innocent until proven guilty. This rule applies in all criminal cases from arrest until conviction or acquittal. However, sometimes the accused person has to adduce sufficient evidence of a particular point in the defence case in order to raise that issue as a defence. As a general rule, once a defence has been raised, the prosecution must prove that it does not apply. In some cases the burden of proof of a particular defence, such as insanity, may rest with the accused.

BEYOND REASONABLE DOUBT

The magistrate, judge or jury, as the case may be, must be satisfied beyond a reasonable doubt that the accused person is guilty. If there is any reasonable doubt he or she should be found not guilty and acquitted.

IGNORANCE OF THE LAW

In proving its case the prosecution does not have to show that the accused person knew that what he or she was doing was against the law. Ignorance of the law is not a valid excuse for an act or omission unless knowledge of the law by the offender is expressly declared to be an element of the offence (s.22 Criminal Code).

THE RIGHT TO REMAIN SILENT

The so called right to remain silent applies throughout the criminal process from arrest until conviction or acquittal. The general rule is that an accused person is not required to answer questions put to him or her by the police nor to give evidence in his or her defence. An important consequence of the rule is that a judge is not entitled to comment adversely on the failure by an accused person to answer police questions or give evidence; in other words no one can suggest that an accused person’s silence is indicative of guilt.

There are some important exceptions to the rule. For example, a failure by a person found in possession of stolen property to give any innocent explanation he or she has for possession of that property may, in some circumstances, be used as evidence of guilt.

Police officers have the power under the Criminal Investigation (Identifying People) Act 2002 (WA) to request the personal details (name, address and date of birth) of a person, where they reasonably suspect that the person has committed or is about to commit an offence, or where they reasonably suspect that the person may be able to assist in the investigation of an offence or a suspected offence. In other words, the Act does not empower a police officer to stop a person and require his or her name and address for no reason at all.

A person who does not comply with a lawful request for their personal details commits an offence (s.16 Criminal Investigation (Identifying People) Act).

DOUBLE JEOPARDY

It is a general principle of criminal law, known as double jeopardy, that no person should be punished more than once for the same offence. t is a complete defence to a criminal charge to show that a person has already been tried and convicted or acquitted of the same offence or for the same act or omission (s.17 Criminal Code (WA)).