Is the test of substantial probative value too high?

12.26 In R v Lockyer, Hunt CJ at CL indicated that ‘substantial probative value’ imposes a higher standard of relevance than ‘significant probative value’, which requires the evidence in question to be ‘important’ or ‘of consequence’.^[27]

12.27 It has been suggested in some consultations and submissions that the requirement of substantial probative value is too high and might exclude evidence relevant to credibility, which on its own would not have substantial probative value but in combination with other evidence would do so.^[28] This is a matter of particular concern for the defence in criminal proceedings where cross-examination is often the primary means of challenging the prosecution case.^[29]

The Commissions’ view

12.28 Limiting credibility evidence in cross-examination to matters of substantial probative value is designed to confine evidence on collateral issues to that which will have a genuine bearing on the assessment of the evidence. Many matters can be said to go to a witness’ credit or discredit, but will not have an impact on the assessment of the veracity and accuracy of that witness’ evidence. Where the evidence is not of substantial probative value in the assessment of a witness’ credibility, at best it adds unnecessarily to the length of trials. At worst it prejudices the proper assessment of the witness’ credibility by the tribunal of fact and distracts from the facts in issue to be determined. Section 103 provides a formal means which does not exist at common law appropriately to limit cross-examination.

12.29 Concern is expressed that the probative value of a line of cross-examination might not be apparent in the first question asked and may therefore be excluded under the rule. The Commissions consider that this concern is unfounded. The Commissions have not identified any cases in which a line of cross-examination with substantial probative value has been stopped because a single question did not meet that test.^[30] In practice, if objection is taken to cross-examination as lacking substantial probative value, counsel can outline the probative value of the line of questioning,^[31] if need be, in the absence of the witness and jury.^[32] This allows the court to rule on the line of questioning without prejudicing the forensic technique of the cross-examiner. There is no reason to suppose that where objection is taken, rulings are made without considering the evidence in the context of the case as a whole.^[33]

12.30 The Commissions do not recommend any amendment to s 103 to broaden the scope for admission of credibility evidence.