**4.2 Hashi v The Queen**

*Forensic Analysis - Scientific and Medical Techniques and Evidence under the Microscope*

*Lord Simon in Kilbourne [1973] AC 729, 756 D.*

*not susceptible to this sort of scientific discipline..."*

*33. If these two conditions are met and the evidence of the witness is admissible, although the weight to be attached to his opinion must of course be assessed by the tribunal of fact: Robb [1991] 93 Cr App R 161, 165; Darragher [2002] EWCA Crim 1903, [2003] 1 Cr App R 12 para 23 ... It might added that, as with any evidence, expert testimony will not be admitted unless it is relevant in the sense that "it is logically probative or disapprobative of some matter that requires proof": per* 

*34. As we have indicated, the appellants argued that evidence should not be admitted unless it passes a certain test, that the evidence can seen to be reliable because the methods used are sufficiently explained to be tested in cross-examination and so to be verifiable or falsifiable. Where, as here, the Crown is seeking to adduce the evidence in a criminal trial, this could properly be considered by the court when deciding whether to refuse to allow the evidence, under Section 78 of the Police and Criminal Evidence Act 1984 or otherwise, in order to ensure a fair trial. We cannot accept that this is a requirement of admissibility. In established fields of science, the court may take the view that expert evidence would fall beyond the recognised limits of the field or that methods are too unconventional to be regarded as subject to the scientific discipline. But a skill or expertise can be recognised and respected, and thus satisfy the conditions for admissible expert evidence, although the discipline is* 

Ultimately, the Court of Appeal in *Otway* upheld the trial judge's conclusion that the evidence of Mr. Blake, in the absence of contradiction, was sufficient to establish the existence of (1) the science or expertise; (2) the witness's proficiency in it; and (3) the foundation for the witness's opinion. It accepted ([6] at [22]) the

*in a comparison exercise based upon facial mapping or walking gait, it is a necessary condition of admissibility that the witness is able to demonstrate to the court the features of comparison upon which his opinion is formed. Since the comparison is visual, an inability by the witness to explain and demonstrate the features upon which his opinion is formed not only places in doubt the existence of the science or technique claimed; it undermines the foundation of reliability required. We have read a transcript of Mr. Blake's evidence and we have viewed the recorded material from which he demonstrated the foundation for his opinion. We entertain no doubt that the jury was in a position to follow and assess the value of his evidence. There is no danger here that the jury was being invited simply to take Mr. Blake's comparison on trust. We agree with Maddison J, however, that Mr. Blake's ability safely to express his ultimate conclusion in terms of probability of a match, even probability based on Mr. Blake's clinical experience, was insufficiently established. It is important that juries are not misled to an over-valuation of comparison evidence.*

While the Court declined leave to appeal, it was circumspect in its expression of its reasons and concerned not to be seen to be accepting of this novel form of

*We do not wish it to be thought that we are endorsing the use of podiatric evidence in general. Upon the evidence before him and the argument addressed to this court, we conclude that Maddison J was right to rule the evidence admissible. However, each such application must be considered on its own merits. It may well be, as in the present case, that the trial judge will need to be astute when such evidence is admitted that it is strictly confined within the expertise established and that the* 

**10**

argument that:

evidence ([6] at [23]):

In *Hashi v The Queen* [15] a ground of appeal arose from the fact that the prosecution had been permitted to rely upon the evidence of a consultant podiatric surgeon, Mr. Barry Francis, in relation to the similarity of the walking gait of the accused and that of a suspect. He had identified two distinctive aspects of gait – features which he described as an abnormality in the position of body parts in the walking cycle, and flow pattern, which he viewed as a product of the walking cycle, such as its speed or length of stride.

Mr. Francis found six common features between the gait of the suspect and the accused:


Of these features the most prominent was the turning inwards of the left foot. Mr. Francis looked for any dissimilarities between the features of the walking gait of the suspect and the accused man in the recordings and found none. He stated that there was no database against which he could make an assessment of frequency and could only refer to his own clinical experience. This led him to express the view that the left-sided inward turn would be found in under 5% of the population. In his view it could only be caused by injury or by one-sided hypermobility, itself an unusual trait. In the absence of trauma, Mr. Francis stated that he would expect to see knee-knock in less than 10% of the population. He stated that there was no predisposition to the presence of one factor in the presence of the other – they were unconnected so it followed that 'a combination of features was more significant than the presence of any one of them ([15] at [57]).

Hashi relied upon the expert evidence of Mr. Blake, the expert who testified in *Otway.* At the relevant time Mr. Blake was the principal podiatrist at the Nuffield Hospital. His view was that the benchmark material was of insufficient quality to attempt an analysis of walking gait.

The Court of Appeal was provided with background material, including published material in relation to the effect of frame rate on the ability to identify characteristics of gait from CCTV [22] and a Home Office Manual [23] in relation to the screen height on CCTV necessary to discern characteristic detail. It noted that at trial no challenge was made to Mr. Francis' evidence, notwithstanding the view of Mr. Blake. The argument was mounted, though, that Mr. Francis' evidence was unreliable because:


The Court of Appeal accepted that the quality of the CCTV images 'is at times indifferent' and that care is required to ensure that the feature demonstrated is reliably demonstrated ([15] at [74]). The Court did not accept that Mr. Francis' inability to specify in scientific terms how he made allowances for an imperfect image rendered his opinion unreliable or unsafe:

*He and the jury were viewing moving and still images. Mr. Francis was showing to the jury the images in which he saw features of gait and either those features could be seen by the jury or they could not. The jury was directed that they could act on the presence of features only if they could observe the features for themselves. Mr. Francis was saying that he had taken account of the imperfection in the image before declaring his identification of a feature. He showed the jury the image on which he relied to make the identification. He was not saying that, although the feature might not be seen by the jury, he, relying on his expertise, was sure it was present. In any instance in which it was argued that the quality of the image was insufficient to be sure that the feature was present the jury had the means to make the assessment for themselves with the assistance of the evidence of Mr. Blake and the cross-examination of Mr. Francis ([15] at [74]).*

This led the Court of Appeal to conclude that with appropriate judicial instructions the jurors could follow the evidence, evaluate its cogency and make their own decision as to whether the features demonstrated were present in each of the recordings. The Court did not agree with the argument that Mr. Francis should not have been permitted to refer to the frequency with which the features or abnormalities he found in the recordings occurred in the course of his clinical practice: 'It was for the jury to evaluate Mr Francis' evidence in the light of the criticisms levelled at him ([15] at [74]). Thus, it concluded that it was not necessary for the judge to have withdrawn the case from the jury at the close of the prosecution case – 'The jury had been provided with the tools with which to make that assessment: in the case of each image on which Mr Francis relied they had their attention drawn to the factors relevant to it, in particular to the quality of the images and the time lapse by which they were recorded. Mr Francis was closely cross-examined on each feature and each significant image' ([15] at [75]).

Both the *Otway* and *Hashi* decisions by the Court of Appeal determined the forensic gait analysis evidence to be admissible and that the risk of inappropriate

**13**

*Guarding the Gait: Evaluating Forensic Gait Analysis Evidence*

juror deference to the evidence was sufficiently addressed by judicial instructions. This was in spite of the evidence in *Hashi* that bore a numerical component of the frequency of the particular attributes in the population seen clinically by the expert. Both decisions were made prior to the intrusion of a reliability prerequisite into

The most significant Australian authority on forensic gait analysis is the 2020 ruling by Justice Beale in the murder case of *The Queen v Crupi* [16]. Part of the evidence suggesting that Crupi was the murderer was forensic gait analysis evidence given on this occasion not by a podiatrist but by Professor Marcus Pandy, the Chair of Mechanical and Biomedical Engineering at the University of Melbourne. He viewed 95 CCTV clips and was asked to identify and document any physical characteristics viewed in them. He measured certain spatio-temporal features of the gait of the subjects using a Google Earth measurement tool – step length, step frequency and walking speed. He found the step lengths of the subjects were consistently around the same value. In his first report he did not express any opinion as to whether or not the subjects of the clips were the same person but concluded that the mean step length and mean walking speed of the subjects were more consistent with the persons being elderly, as was the degree of toe-out gait – the relevance of this to the prosecution was that Crupi was aged 67 at the time of the murder.

On the basis of the first report by Professor Pandy, he was asked to offer a further opinion as to whether 'a person recorded in any of the CCTV footage contained in clips 1 to 36 is the same as a person recorded in any of the CCTV footage contained in clips 37 to 95'. Police also provided more precise measurements between various geographical features shown in the clips so that Professor Pandy could calculate the relevant spatio-temporal gait features of the subjects more accurately, rather than relying on the Google Earth measuring tool. Professor Pandy concluded that the subjects walked with a gait pattern 'more consistent with that exhibited by older adults, who take shorter steps and walk more slowly than healthy young

The cross-examination of Professor Pandy proved important. He disavowed being an expert on whether persons were similar or dissimilar and said he had never done any research regarding the pitfalls in making such a comparison. He said he was not familiar with the concept of confirmation bias ([16] at [29]). Professor Pandy said he was not a statistician but had sufficient knowledge of statistics to calculate standard deviations. He said there was no way of assessing whether the subjects in any of the clips were walking at their preferred speed and agreed that sometimes he had had to round down the number of steps taken between the relevant locations. He also conceded that he sometimes had to make a judgement as to when a subject's heel struck the ground ([16] at [32]) and that the subjects did not always walk in a straight line between the points. He sometimes observed excessive

Professor Pandy said he had never previously been asked to compare CCTV clips of subjects, that he knew nothing about the make or model of the CCTV cameras capturing the relevant images or whether they distorted the images. He conceded he had no information about the frame rates of the CCTV clips and agreed that the frame rates could affect the accuracy of his judgements as to when the heel of the subjects struck the ground (at [34]). Importantly, Professor Pandy was not able to shed any light on the statistical significance of his findings compared with the population at large, and did not purport to do so, instead stating that the mean step lengths of

lateral movement in the gait of the subjects ([16] at [33]).

*DOI: http://dx.doi.org/10.5772/intechopen.99491*

English criminal law [2].

**5. Australian authority**

adults' (at [26]).

juror deference to the evidence was sufficiently addressed by judicial instructions. This was in spite of the evidence in *Hashi* that bore a numerical component of the frequency of the particular attributes in the population seen clinically by the expert. Both decisions were made prior to the intrusion of a reliability prerequisite into English criminal law [2].
