The functions of judge and jury:
Judge: The judge decides as a matter of law what evidence they will consider in coming to a decision.
Jury: is the ultimate ‘tribunal of fact’ and the function of the judge is to direct them on points of law and to ensure that they are not misled by inadmissible evidence. This process finds statutory expression in Queensland under the Criminal Code s620.
In practice, the line between these two functions can become somewhat blurred. For example, in deciding as a question of law whether or not a confession is admissible, a judge may be required to consider conflicting factual allegations as to how it was obtained and choose which facts to believe. This will normally be done out of the hearing of the jury in a process known as a voir dire.
If that confession is then admitted, Defence Counsel can re-raise before the jury all the factual disputes raised on the voir dire and invite the jury to conclude that the confession was involuntary, which is in essence a question of law. By the same process Defence Counsel can also severely reduce the amount of weight that the jury will attach to the confession.
The jury is the ultimate arbiter of fact but the judge controls what facts they are allowed to hear. The rules under which the judge does so are called ‘the laws of evidence’.
Types and Classifications of Evidence:
Oral Evidence: verbal testimony of a witness in court. That witness will, ideally, be speaking to something that they perceived with their own senses (sight, sound, smell etc), and if they seek instead to relate what someone else perceived and then communicated to them, then their testimony may well be rejected as hearsay. In some cases, although the witness is required to enter the witness box and answer questions, the importance of their evidence lies not in what they perceived but in the assistance that they are able to give to the court in interpreting facts spoken to by others, or objects connected with the matter under investigation.
Direct evidence: witness X states that they saw A hit B, then in an assault trial this is direct evidence. ‘Direct’ evidence is evidence that leads directly to the proof of a fact in issue.
Circumstantial evidence: their evidence is to the effect that they saw A running from the scene of the assault, then that evidence is circumstantial. ‘Circumstantial’ evidence is indirect evidence of a fact in issue.
Real evidence: ‘Real evidence’ is the term used to describe all the evidence that may be obtained from a ‘thing’. Examples include: Photographs of a scene, such as those of the general location in which a dead body was found.
Competence and Compellability:
Competence: A person is ‘competent’ to testify if they are allowed to do so by law.
Compellability: A person is ‘compellable’ as a witness if they may be obliged to give evidence by law (under threat of a charge of contempt of court).
The general rule is that everyone is both a competent and a compellable witness.
This is, in origin, a common law rule that both grants competence and enforces compellability on everyone to whom no statutory exception applies. This principle has found statutory expression in the Uniform Laws: see Evidence Act 1995 (Cth) s12 (b) for further information.
Cross-examination of an ACCUSED who testifies:
Once an accused becomes a witness-even on their own behalf-they will be exposed to cross-examination by the Crown just like other Defence witness. If they were allowed to claim in respect of the very offences of which they stand charged, the privilege against self-incrimination that is afforded to normal witnesses this cross-examination would be a farce.
S618 of the Criminal Code (QLD) provides that at the close of the Crown case, the accused must be given an opportunity to indicate whether or not they intend to lead evidence either by testifying personally or by calling other witnesses. This is particularly important when an accused is unrepresented, and the issue of how much advice should be given to such an accused by a notionally neutral trial judge was considered by the High Court in MacPherson v The Queen (1981) 147 CLR 512.
 Hoskyn v Metropolitan Police Commissioner  AC 474 at 489.