Ground 5. His Honour erred in permitting cross-examination of the witness Donnelly about different conclusions reached by another witness in another case.
54 Mr Donnelly was asked whether he was aware of another case - which may well have been R v Rozynski (unreported, CCA, 1 February 1996) - in which a Dr David Lowe, who Mr Donnelly said he understood was a specialist in computer imaging, was involved in estimating heights from a video recording, and it was suggested that Dr Lowe had come to a conclusion different from that reached by Mr Donnelly in that case. It would appear from at least one of Mr Donnelly's early answers that the two used the same or a similar method although Mr Donnelly said that one of the methods contained additional parameters. The evidence also established that Mr Donnelly was one of two persons who had signed a discussion or rebuttal of the report Dr Lowe had written in that case. Mr Donnelly gave a non-responsive answer to the effect that his co-author had the view that Dr Lowe's method had some serious problems with it.
55 The Prosecutor than asked "If I can hand you a report from Dr David Lowe. If I can get you to look at the summary section?" and objection was taken. The Prosecutor indicated that his aim was to establish that it was an inexact science in which Mr Donnelly was involved and that experts differed in their results. Mr Stratton, the defence counsel, submitted that there were two problems with what was sought to be done. He identified them as follows: For the difference in results to have any weight one would need to establish that there was some validity in the other assessment and there was no evidence of that. Secondly, the witness was being cross-examined on someone else's document and it could not be admissible.
56 The Crown Prosecutor's aim was, in our view, legitimate even though there had been no evidence called in the Crown's case in chief and no certainty that the Crown would be allowed to call a case in reply. Furthermore, it does not seem to us that the first of the objections raised provided a reason why the cross-examiner should not have been allowed to continue in his task. Mr Donnelly might have provided the evidence or, even if Mr Donnelly did not, Mr Donnelly's answers might have induced the jury to have doubts concerning Mr Donnelly's result. However the form which the cross-examination subsequently took, and which was foreshadowed in the Crown Prosecutor's remarks quoted, certainly offended s44 of the Evidence Act (and but for that Act, was objectionable anyway - see Alister v R (1983-4) 154 CLR 404 at 464; R v Hawes (1994) 35 NSWLR 294 302D-303F). Section 44, so far as is relevant, provides:-
"(1) Except as provided by this section, a cross-examiner must not question a witness about a previous representation alleged to have been made by a person other than the witness.
(2) A cross-examiner may question a witness about the representation and its contents if:
(a) evidence of the representation has been admitted, or
(b) the court is satisfied that it will be admitted.
(3) If subsection (2) does not apply and the representation is contained in a document, the document may only be used to question a witness as follows:
(a) the document must be produced to the witness,
(b) …
(c) the witness must be asked whether, having examined … the contents of the document, the witness stands by the evidence that he or she has given,
(d) neither the cross-examiner or the witness is to identify the document or disclose any of its contents."
57 Nevertheless, the trial judge said that he would allow the question, shortly thereafter indicating that he was disinclined to allow the Crown to call Dr Lowe in reply. When cross-examination resumed, Mr Donnelly was taken to Dr Lowe's report, which was again described, and the response. Mr Donnelly agreed that Dr Lowe had concluded that the height of the person in that case was 1.78m and that this differed from that arrived at by Mr Donnelly and his co-author by 9 cm. Mr Donnelly went on to say that the respective methods differed and that different methods would yield different results.
58 The topic was taken up again in re-examination. Having re-iterated his own qualifications and expertise and said that Dr Lowe's background was in computers, Mr Donnelly then gave evidence to the effect that he would not regard someone who had expertise in computer system engineering as being an expert in determining measurements from photos. He said that he had had a further short look at Dr Lowe's report and that Dr Lowe's method was quite different and not safe.
59 It was submitted on behalf of the Crown that the evidence to which we have referred could have been obtained by proper cross-examination and, in any event, the re-examination more than adequately dispelled any disadvantage the Appellant may have suffered from the cross-examination. We doubt the first and do not agree with the second of these propositions. Prior to the attempt to hand Dr Lowe's report to Mr Donnelly, the latter had given evidence to the effect that he had no recollection of Dr Lowe's findings which Mr Donnelly described as "of three years ago". Adherence to those requirements of s44 as proscribed identification of Dr Lowe's report and its contents would have avoided the jury being informed of Dr Lowe's conclusions, their authorship and, by implication, the authority behind them. The jury's knowledge of these matters, obtained by the questioning in breach of s44, might well have led them to place less, and considerably less, weight on the principal evidence which Mr Donnelly was called to give. Thus the Crown derived a significant advantage in consequence of the breach of s44.
60 The nature of the identification evidence, and the summary of it given above demonstrate that it was very far from being conclusive. Given the importance to the defence case of the evidence of Mr Donnelly, it follows that the Appellant's conviction could not stand. It was for this reason that the Court allowed the appeal.