**4. English authority**

Although gait analysis evidence was permitted in the 1839 case of *R v Thomas Jackson* where the accused was identified by his bowed left leg and his propensity to walk with a limp, and was admitted in an armed robbery trial in the Old Bailey in 2000 in relation to a suspect said by a podiatrist to have a bow-legged gait encountered in only 5% of the United Kingdom population, (*R v Saunders*: see [5]), there are two major English appellate decisions in relation to gait analysis.

#### **4.1 R v Otway**

In *Otway v The Queen* [6], evidence in relation to walking gait analysis was adduced in a murder trial by the prosecution from CCTV images which depicted 20 seconds of an offender in motion. The driver and a passenger of a motor vehicle approached the deceased man and the passenger shot him dead. Otway was alleged by the prosecution to be the driver and was convicted on the basis of being participant in a joint homicidal enterprise.

The witness who gave the gait analysis evidence was a Mr. David Blake, who described himself as a 'podiatrist and specialist in lower limb gait, pathomechanics and biomechanics' ([6] at [10]). He said that he routinely used video camera equipment to analyse gait clinically to assess and diagnose anatomical and skeletal conditions. He described the practice of gait analysis ([6] at [10]) as follows:

*Gait analysis is the examination of walking or running. The gait, or walking cycle, skeletal movement in general can have recognised anatomical movements or reference points during a walking cycle. Biomechanics is the examination and analysis of body movement. Specifically in this case to humans the skeleton can at times give an anatomical signature that if not unique, can be a relatively rare anatomical position or movement to a few individuals. A person's walking cycle or his skeletal anatomy is difficult to hide as it is part of their body's anatomy. The science of gait analysis was introduced into the UK and the profession of podiatry in the early 1970s. The gait cycle can be broken down into factors such as the position of feet and other parts of the lower limb. Thus features of gait can be identified and sometimes quantified. Podiatrists use gait analysis virtually every day in their practice. Recently that science has been applied forensically. The Council for the Registration of Forensic Practitioners recognises gait analysis and footprint identification as important components in identification of individuals. A podiatric section has recently been set up … some clinicians may suggest that certain key elements of gait cycle or biomechanical (body) position and movement can leave a unique signature confirming that an individual in comparison is one of the same …*

Mr. Blake stated that he saw approximately 2,000 patients per year in his practice as a podiatrist and that it was highly unusual to see a skeletal structure that has a linear spine without some scoliosis or lordosis, namely one form or another of curvature. He concluded that Otway, in common with the driver of a motor vehicle observed on CCTV, had an unusually erect posture. Mr. Blake estimated that only in about 7% of his practice population did he find 'the slight neck flexion or head poke where the head is projected excessively forward' which he observed in the recordings of the offender and of Otway.

At trial it was argued for the defence that the analysis offered by Mr. Blake could be undertaken by the jurors themselves unassisted by expert evidence ([6] at [11]) and that there was no statistical database against which the jury could judge the

**9**

*Guarding the Gait: Evaluating Forensic Gait Analysis Evidence*

significance of his evidence. In addition, it was contended that there was no scientific basis, and no measurement, to support Mr. Blake's methodology. The trial judge ruled that Mr. Blake should be permitted to give evidence in which he identified the similarities between the walking gait of the appellant and the walking gait of the suspect. It was for the jurors to assess that evidence having viewed the recorded material for themselves. Mr. Blake, however, was not permitted to give evidence relating to the facial features of the appellant or the suspect, and was not permitted to evaluate his comparison of walking gait by reference to the chance that the driver of the motor vehicle at the petrol filling station was someone other than the

The Court of Appeal received evidence from a professor who was an expert in biology and genetics and who argued that there was an absence of evidence about whether the technique employed by Mr. Blake had been tested in field conditions, subjected to peer review and publication or known rate of error, or subjected to verifiable standards. The Court of Appeal observed that the professor was not a podiatrist and not in a position to express an opinion as to whether Mr. Blake had the expertise which he purported to employ in his analysis. It observed too that in *Re T* [19] at [92]–[96], Thomas LJ giving the judgement of the court, made reference to several cases in which, by reason of the subject matter of the expert evidence, the expert was unable to evaluate their findings by reference to a database

*Nevertheless the evidence of evaluation, founded upon and explained to be the consequence of personal experience, was properly admitted. The proposition that evidence of a comparison cannot be admitted if its evaluation is expressed in terms* 

facial mapping evidence in which ([18] at [23]) Lord Justice Hughes stated:

*would be to give the jury raw material with no means of evaluating it.*

The Court of Appeal applied the reasoning in *Atkins & Atkins*, a case involving

*An expert who spends years studying this kind of comparison can properly form a judgement as to the significance of what he has found in any particular case. It is a judgement based on his experience. A jury is entitled to be informed of his assessment. The alternative, of simply leaving the jury to make up its own mind about similarities and dissimilarities, with no assistance at all about their significance,* 

It noted the words of Lord Justice Rose in the 2004 decision of the English Court

*"32. For expert evidence to be admissible, two conditions must be satisfied: first, that study or experience will give a witness's opinion an authority which the opinion of one not so qualified will lack; and secondly the witness must be so qualified to express the opinion. The first was elucidated in Bonython [1984] 38 SASR 45, where King CJ (at p.46) said that the question "may be divided into two parts: (a) whether the subject matter of the opinion is such that a person without instruction or experience in the area of knowledge or human experience would be able to form a sound judgement on the matter without the assistance of witness possessing special knowledge or experience in the area, and (b) whether the subject matter of the opinion forms part of a body of knowledge or experience which is sufficiently organised or recognised to be accepted as a reliable body of knowledge of experience, a special acquaintance with which by the witness would render his opinion of* 

*subjective experience is simply wrong in law (at [20]).*

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

appellant.

of random selection:

of Appeal in *R v Luttrell* [21]:

*assistance to the court.*

*Guarding the Gait: Evaluating Forensic Gait Analysis Evidence DOI: http://dx.doi.org/10.5772/intechopen.99491*

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

are two major English appellate decisions in relation to gait analysis.

Although gait analysis evidence was permitted in the 1839 case of *R v Thomas Jackson* where the accused was identified by his bowed left leg and his propensity to walk with a limp, and was admitted in an armed robbery trial in the Old Bailey in 2000 in relation to a suspect said by a podiatrist to have a bow-legged gait encountered in only 5% of the United Kingdom population, (*R v Saunders*: see [5]), there

In *Otway v The Queen* [6], evidence in relation to walking gait analysis was adduced in a murder trial by the prosecution from CCTV images which depicted 20 seconds of an offender in motion. The driver and a passenger of a motor vehicle approached the deceased man and the passenger shot him dead. Otway was alleged by the prosecution to be the driver and was convicted on the basis of being partici-

The witness who gave the gait analysis evidence was a Mr. David Blake, who described himself as a 'podiatrist and specialist in lower limb gait, pathomechanics and biomechanics' ([6] at [10]). He said that he routinely used video camera equipment to analyse gait clinically to assess and diagnose anatomical and skeletal conditions. He described the practice of gait analysis ([6] at [10]) as

*Gait analysis is the examination of walking or running. The gait, or walking cycle, skeletal movement in general can have recognised anatomical movements or reference points during a walking cycle. Biomechanics is the examination and analysis of body movement. Specifically in this case to humans the skeleton can at times give an anatomical signature that if not unique, can be a relatively rare anatomical position or movement to a few individuals. A person's walking cycle or his skeletal anatomy is difficult to hide as it is part of their body's anatomy. The science of gait analysis was introduced into the UK and the profession of podiatry in the early 1970s. The gait cycle can be broken down into factors such as the position of feet and other parts of the lower limb. Thus features of gait can be identified and sometimes quantified. Podiatrists use gait analysis virtually every day in their practice. Recently that science has been applied forensically. The Council for the Registration of Forensic Practitioners recognises gait analysis and footprint identification as important components in identification of individuals. A podiatric section has recently been set up … some clinicians may suggest that certain key elements of gait cycle or biomechanical (body) position and movement can leave a unique signature* 

*confirming that an individual in comparison is one of the same …*

Mr. Blake stated that he saw approximately 2,000 patients per year in his practice as a podiatrist and that it was highly unusual to see a skeletal structure that has a linear spine without some scoliosis or lordosis, namely one form or another of curvature. He concluded that Otway, in common with the driver of a motor vehicle observed on CCTV, had an unusually erect posture. Mr. Blake estimated that only in about 7% of his practice population did he find 'the slight neck flexion or head poke where the head is projected excessively forward' which he observed in the record-

At trial it was argued for the defence that the analysis offered by Mr. Blake could be undertaken by the jurors themselves unassisted by expert evidence ([6] at [11]) and that there was no statistical database against which the jury could judge the

**4. English authority**

**4.1 R v Otway**

follows:

pant in a joint homicidal enterprise.

ings of the offender and of Otway.

**8**

significance of his evidence. In addition, it was contended that there was no scientific basis, and no measurement, to support Mr. Blake's methodology. The trial judge ruled that Mr. Blake should be permitted to give evidence in which he identified the similarities between the walking gait of the appellant and the walking gait of the suspect. It was for the jurors to assess that evidence having viewed the recorded material for themselves. Mr. Blake, however, was not permitted to give evidence relating to the facial features of the appellant or the suspect, and was not permitted to evaluate his comparison of walking gait by reference to the chance that the driver of the motor vehicle at the petrol filling station was someone other than the appellant.

The Court of Appeal received evidence from a professor who was an expert in biology and genetics and who argued that there was an absence of evidence about whether the technique employed by Mr. Blake had been tested in field conditions, subjected to peer review and publication or known rate of error, or subjected to verifiable standards. The Court of Appeal observed that the professor was not a podiatrist and not in a position to express an opinion as to whether Mr. Blake had the expertise which he purported to employ in his analysis. It observed too that in *Re T* [19] at [92]–[96], Thomas LJ giving the judgement of the court, made reference to several cases in which, by reason of the subject matter of the expert evidence, the expert was unable to evaluate their findings by reference to a database of random selection:

*Nevertheless the evidence of evaluation, founded upon and explained to be the consequence of personal experience, was properly admitted. The proposition that evidence of a comparison cannot be admitted if its evaluation is expressed in terms subjective experience is simply wrong in law (at [20]).*

The Court of Appeal applied the reasoning in *Atkins & Atkins*, a case involving facial mapping evidence in which ([18] at [23]) Lord Justice Hughes stated:

*An expert who spends years studying this kind of comparison can properly form a judgement as to the significance of what he has found in any particular case. It is a judgement based on his experience. A jury is entitled to be informed of his assessment. The alternative, of simply leaving the jury to make up its own mind about similarities and dissimilarities, with no assistance at all about their significance, would be to give the jury raw material with no means of evaluating it.*

It noted the words of Lord Justice Rose in the 2004 decision of the English Court of Appeal in *R v Luttrell* [21]:

*"32. For expert evidence to be admissible, two conditions must be satisfied: first, that study or experience will give a witness's opinion an authority which the opinion of one not so qualified will lack; and secondly the witness must be so qualified to express the opinion. The first was elucidated in Bonython [1984] 38 SASR 45, where King CJ (at p.46) said that the question "may be divided into two parts: (a) whether the subject matter of the opinion is such that a person without instruction or experience in the area of knowledge or human experience would be able to form a sound judgement on the matter without the assistance of witness possessing special knowledge or experience in the area, and (b) whether the subject matter of the opinion forms part of a body of knowledge or experience which is sufficiently organised or recognised to be accepted as a reliable body of knowledge of experience, a special acquaintance with which by the witness would render his opinion of assistance to the court.*

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

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

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 argument that:

*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 evidence ([6] at [23]):

*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* 

**11**

*Guarding the Gait: Evaluating Forensic Gait Analysis Evidence*

*the permissible scope of the evidence if admitted.*

1.On the left side the toe was turned inwards;

*proper limits of evaluation are identified from the outset. We endorse, with respect, the views of the court in T (paras 97–99) as to the necessity for the parties to have issues of disclosure and admissibility well in mind during preparation for the case management hearing so that, when the appropriate time comes, the trial judge is presented with all the material needed to make an assessment of admissibility, and* 

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,

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

3.The stance was upright without head-poke (that is, without the head being

5.There was a narrow base of gait (that is, the legs passed close together in the

6.When the suspect turned, he did so from the waist rather than the neck ([15]

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

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

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

4.There was a long stride with ankle movement in the stride;

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

**4.2 Hashi v The Queen**

accused:

2.Knee-knock;

stride);

at [56]).

them ([15] at [57]).

attempt an analysis of walking gait.

thrust forward);

such as its speed or length of stride.

*proper limits of evaluation are identified from the outset. We endorse, with respect, the views of the court in T (paras 97–99) as to the necessity for the parties to have issues of disclosure and admissibility well in mind during preparation for the case management hearing so that, when the appropriate time comes, the trial judge is presented with all the material needed to make an assessment of admissibility, and the permissible scope of the evidence if admitted.*
