House of Commons - Science and Technology

Select Committee on Science and Technology Seventh Report

7 Use of Forensic Evidence in Court

130. In recent years the spotlight has fallen on the use of expert evidence in court, triggered largely by the wrongful convictions of Sally Clark and Angela Cannings for murdering their babies. In both cases, Professor Sir Roy Meadow, a paediatrician of many years' experience, gave expert evidence at the original trials which included flawed statistical calculations. These cases were preceded by cases such as that of the "Birmingham Six", who were freed in 1991 having served 16 years in jail, after their convictions were overturned in part due to discredited forensic evidence. This inquiry has focussed predominantly on the use of forensic evidence by the criminal courts, although many of the points made are of relevance to the civil courts. We acknowledge that we are in danger of straying into areas beyond our remit in looking at the courts, so have sought to confine our comments to the use of science and expert evidence within the courtroom. Where we touch on more fundamental principles of the legal system this is primarily to provide the context for our observations about experts and expert evidence and is not intended to be a thorough analysis of those principles.

Expert witnesses

ROLE OF EXPERTS

131. The purpose of expert evidence is to provide the court with information based on scientific results, the interpretation of which is outside the experience and knowledge of a judge and jury. It is the court's responsibility to decide whether there is a need for expert evidence and also to establish the competency of the expert witness. If the expert evidence is clear and not contradicted by any other evidence, the jury should accept it. If the evidence is not clear, or there is evidence which contradicts the expert's opinion, the jury may reject it. Furthermore, the judgement on Angela Canning's successful appeal against her conviction for murdering her two baby sons stated that "If the outcome of the trial depends exclusively, or almost exclusively, on a serious disagreement between distinguished and reputable experts, it will often be unwise, and therefore, unsafe to proceed".[306]

COUNCIL FOR THE REGISTRATION OF FORENSIC PRACTITIONERS

132. The Council for the Registration of Forensic Practitioners (CRFP) was established in 1999 to give the courts a single point of reference on the competence of forensic practitioners. The overriding aim of the CRFP is "to promote public confidence in forensic practice in the UK".[307] It will achieve this through publication of a register of currently competent forensic practitioners; ensuring that registered practitioners stay up to date and maintain competence; and disciplining registered practitioners who do not meet the required standards.[308] As of February 2005, there were 1,691 names on the register in up to 18 specialist areas ranging from anthropology to road transport investigation.[309] The range of specialities available is currently being expanded to include veterinarians, fire scene examiners, geologists and specialists in digital evidence (computing and imaging).[310] It should be noted that not all of the practitioners registered with CRFP are expert witnesses; many are SOCOs, for example. However, we have focussed our discussion on issues pertaining to CRFP registrants who act as expert witnesses in the courts.

133. The standard for registration is "safe, competent practice".[311] Applicants wishing to join the Register are required to provide details of their qualifications and experience, references from colleagues and users of their services, and declarations about their past and future conduct. An assessor from the relevant specialty will also review a sample of their recent cases against competence criteria that have been developed in association with professional bodies. If successful, the applicant will be granted registration for four years. In order to renew their registration, the practitioner will need to "demonstrate that they have stayed up to date and maintained their competence" and their recent casework will be subjected to a further formal assessment.[312] Where there is a need for disciplinary action against a practitioner, "The action taken will often be educational and remedial; but the ultimate sanction is removal of the practitioner's name from the Register".[313] Since the inception of the Register, disciplinary proceedings have been taken against two practitioners; these were still in progress at the time of publication of this Report.[314]

134. The CFRP register has been welcomed by many as an important step towards a quality control system that ensures that those who present themselves as expert witnesses are competent to fulfil that role.[315] The Prime Minister has said: "Ensuring high standards of professional competence of those experts called to give evidence is crucial to the credibility of the judicial system and the Register is a tool that can do much to underpin that credibility".[316] The FSS has demonstrated its support for the Register by requiring all its reporting officers (court-going scientists) to be registered, and ACPO policy is that police force forensic personnel should be CRFP accredited.[317]

Limitations of the Register

135. Despite the widespread support for the CRFP, various people have identified problems and limitations with the Register as it stands. It has, for example, been asserted that now discredited expert witnesses, including perhaps Professor Meadow, would have had no difficulty in obtaining CRFP registration.[318] Indeed, Professor Meadow became discredited for the flawed statistical evidence that he gave—an area in which he was not expert; his speciality was in paediatrics. Andrew Keogh from Tuckers Solicitors recently criticised the fact that "there is nothing within CRFP that is committed to a remit of evidence-based practice", and suggested that "it would be of more benefit to the criminal justice system if a comprehensive process of research, evaluation and peer review took place on a rolling basis".[319] Karen Squibb-Williams, lawyer and Policy Adviser for the CPS, also expressed concerns about the CRFP. She told us that "registration cannot be a panacea for exercising a judge's discretion" and called for "absolute independence and integrity in the auditing of that registration and validation of the accreditation that goes with it".[320] The CRFP must itself be subject to regular independent auditing of the assessment processes used to grant accreditation and renewal of accreditation, as well as the disciplinary procedures. It is essential that the CRFP is, and is seen to be, transparent, accountable and independent. It must also be seen to exercise its duty of care by vigorous and appropriate actions in respect of malpractice allegations about registrants.

136. Professor Sue Black, a CRFP-registered forensic anthropologist, also highlighted the limitations of the CRFP register for a small specialist community such as hers. She pointed out that the members of this community were all responsible for accrediting each other and that they had a vested interest in increasing the number of people in their field with CRFP registration since this would eventually bring more people into the discipline.[321] Equally, there could be a problem of competition between members of a specialism interfering with the peer review process that underpins accreditation. As the community of registrants grows in an emerging specialism, the problems associated with the small number of possible assessors should diminish. In the meantime, CRFP must take care to monitor the assessment process carefully, if necessary using the services of overseas experts with appropriate experience and expertise.

Voluntary/mandatory registration

137. At present, CRFP registration is voluntary for expert witnesses and the CRFP, Bar Council and Crown Prosecution Service (CPS) all indicated that they opposed the idea of mandatory registration. The CRFP, for example, stated in written evidence that "in a free society no one should seek to constrain the courts as to the evidence they can hear; and there will always be situations where evidence is required from an expert in a very small specialty or one whose expertise is needed in court too rarely to justify maintaining a registration scheme". A requirement for an expert witness to have CRFP registration could also be problematic for cases where forensic practitioners based outside the UK are called to give expert evidence.

138. Professor Evelyn Ebsworth, Chairman of the CRFP, told us that he would be "very happy if all the organisations employing people to give evidence regularly in courts were to insist, as employers, that people should be registered", and hoped that, as the Register expands, "courts will ask if [expert witnesses] are registered, and, if they are not, they will ask why not".[322] CRFP also told us that the Legal Services Commission, which must authorise the use of experts by solicitors in order to guarantee payment, was in the process of considering whether to use the CRFP Register "as an indicator, so that solicitors who use registered practitioners will have to provide less justification than those who do not".[323]

139. Alan Kershaw, Chief Executive of the CRFP, estimated that, "in the mainstream specialities", around 40% of the potential pool of practitioners have taken CRFP registration to date.[324] Providing that the current problems with the Register can be resolved, as the percentage of registered practitioners in the mainstream specialities increases, there will be a strong case for CRFP registration being made mandatory for experts in those specialities presenting evidence to the courts. This would not prevent the courts from hearing evidence from an expert in a speciality for which CRFP had not achieved a critical mass of registrants, or from experts based overseas. The Forensic Science Society should also consider making CRFP registration a condition of membership for active practitioners in order to stimulate uptake of accreditation.

PRESENTATION OF EVIDENCE

140. During the course of this inquiry we heard much evidence to suggest that the weight ultimately attached to expert evidence by juries is determined in significant part by the way in which the evidence is presented. Professor Sir Alec Jeffreys told us in oral evidence: "I lost my faith in the adversarial system the first time I stood up in court", due to the realisation that "it all depends on the chemistry between the witness and the jury".[325] In addition, following the successful appeal of Angela Cannings, Dr Chris Pamplin, editor of the UK Register of Expert Witnesses, asserted that "Roy Meadow did come to have that element of desirability in the eyes of the CPS" and warned that "Undoubtedly, there are some expert witnesses which when they stand up in court bring with them a very strong persuasive element to their evidence. And their evidence takes on a greater weight because of the way they deliver it".[326] It is worth noting that forensic science textbooks even advise experts to consider their manner of dress and appearance when giving expert testimony: a recently published book by the Royal Society of Chemistry observes that "it may be that the demeanour of the expert leaves as much of an impression on the jury as what was actually said. For these reasons an expert who is to appear in court must take particular care with such fundamental items as dress and appearance".[327]

141. Professor Sue Black, a forensic anthropologist with considerable experience of appearing as an expert witness, identified a related problem: "when the defence ask who is the prosecution witness on this then frequently there are a number of people who will back down and will not go up in court against them".[328] She attributed this to the fact that "they believe that the person the prosecution has aimed for is going to have greater credibility, greater presence and greater ability in court" and described the "great scrambling in a lot of police forces to make sure that they get the person they want in the prosecution".[329] She herself said she had "first-hand experience of that, of being brought into a number of police forces to ensure that I was not brought in with the defence" and said that there was "unquestionably a league table among expert witnesses".[330] ACPO subsequently stated that they agreed with Professor Black's observation, conceding that "some experts are perceived to have more credibility and are more persuasive than others", although noting that the police preference for certain witnesses may also reflect their greater skill or experience.[331] Either way, this does not seem to be likely to advance the prospects of a fair trial.

142. We put these points to the CPS and received the following answer from Nimesh Jani, Policy Adviser and lawyer for the CPS: "That may be true of any evidence that juries will hear, and it is probably true whether it be the defence lawyer or the prosecution lawyer, if they have the charisma to entertain juries properly […] At the end of the day, juries are there to judge the facts and that includes how people come across—inappropriately of course not, but appropriately yes".[332] We are disappointed to discover such widespread acknowledgement of the influence that the charisma of the expert can have over a jury's response to their testimony, without proportional concomitant action to address this problem. If key players in the criminal justice system, including the police and experienced expert witnesses, do not have faith in a jury's ability to distinguish between the strength of evidence and the personality of the expert witness presenting it, it is hard to see why anyone else should. There is clearly no easy answer to this problem, but that does not justify the complacent attitude of the CPS. Possible steps that could be taken to ameliorate the situation are discussed in below.

TRAINING OF EXPERTS

143. In view of the emphasis placed on the importance of presentation of evidence, we were interested to know what training experts typically received in this area. Staff of the FSS and the other main providers are likely to receive training in the presentation of evidence to courts from their employer and the CPS drew our attention to the many seminars and courses provided by bodies such as the Expert Witness Institute. However, we heard that not all independent forensic practitioners, for example academics, were obtaining adequate training. Professor Black from the University of Dundee told us in oral evidence that "many of the professionals who are considered to be expert witnesses in court […] frequently receive no instruction of what is required of them". As a result, "they find the experience to be wholly unpleasant and feel that they have not presented in the way in which they had anticipated they would".[333]

144. The report of the working group of the Royal College of Pathologists and the Royal College of Paediatrics and Child Health on sudden unexpected death in infancy also commented on the detrimental effect of the lack of appropriate training for doctors appearing as expert witnesses: "Unfortunately, there is insufficient training emphasis on the necessity of a scientific foundation for expert testimony. Nor are doctors sufficiently trained in the differences between the [family and criminal] courts".[334] The report further recommended that "Doctors should have special instruction on the role of the expert witness before holding themselves out as court experts" and that "Such instruction should be renewed at least every five years".[335] In addition, the Bar Council said that training of expert witnesses would be "a welcome development" and asserted that a "government grant for training experts in presentational skills and the legal process would be justified in terms of the value it would give to the system".[336] The training of expert witnesses in the general principles of presentation of evidence to courts and the legal process is essential. For independent forensic practitioners and those who would not otherwise receive such training, the Department for Constitutional Affairs should make funding available to ensure that they do have access to this training in advance of their appearance in court.

145. A recent article in the New Law Journal pointed out that "there is no such thing as registered or approved witness preparation trainer, and no code of practice specifically on the topic".[337] This is important because there is a need to distinguish between legitimate witness training and prohibited witness "coaching". The case of R v Salisbury (June 2004) established the legitimacy of training to familiarise witnesses with the general principles of giving evidence in court and how best to prepare for this experience. The training concerned was not tailored to the case in question, did not rehearse any possible lines of questioning, nor discuss any of the evidence relating to the case, all of which could have fallen into the realm of witness coaching. Nevertheless, this is a thorny subject, as reflected by the recent ruling in the Court of Appeal which stated that "training or coaching witnesses in criminal proceedings, whether for prosecution or defence, was not permitted".[338] In our view, in interpreting these rulings a distinction must also be made between ordinary witnesses and expert witnesses since the jury's expectations of these two classes of witness are likely to be very different. The credibility of an expert witness may well be undermined if they appear confused or unsettled by the court process, irrespective of the strength of their expertise. There is a need for clear guidelines to be issued setting out the acceptable areas of training for witnesses. These guidelines must also take into account the special status of expert witnesses, as distinct from ordinary witnesses. In addition, the guidelines should clearly differentiate between the roles of experts in the family, civil and criminal courts.

Adversarial system

146. The UK—like the US and most other Commonwealth—uses an adversarial system for trials. This is in contrast to the inquisitorial approach of civil law followed by many European countries. According to the UK common law tradition, witnesses are called by the prosecution or defence for the purposes of answering questions and are subsequently subjected to cross-examination by the other party. The judge does not call or examine witnesses: the role of the judge is to make decisions on points of law. In an adversarial system, expert witnesses, like ordinary witnesses, are called to provide evidence to strengthen the case of the relevant party. Opinions expressed by ordinary witnesses are not admissible by evidence: it is the responsibility of the judge, in civil cases, and the jury, in criminal cases, to draw inferences from the facts before the court. However, expert witnesses may assist the judge and jury in drawing these inferences and are therefore permitted to express their expert opinion.

147. It is clearly stated that the primary responsibility of the expert witness must be to the court. It is also clear that the expert must not present a biased opinion, the test for impartiality being whether the same expert opinion would have been given if the other party had commissioned the report. Nevertheless, there is a commonly held perception that expert witnesses are effectively "hired guns". An anonymous survey of 133 expert witnesses conducted by the training firm Bond Solon in November 2002 revealed that 58% of expert witnesses did not think that lawyers encouraged their expert to be a "truly independent witness" and 53% of respondents said that there were firms of solicitors with whom they would never work again (although the reasons for this were not explored).[339]

148. The 2002 review of the investigation and prosecution arising from the murder of Damilola Taylor also highlighted the need to ensure that the defence does not "shop around" for an expert whose evidence is most favourable to their case, recommending that "there should be a general principle of reciprocity attaching to the duty of disclosure, including that the defence should be obliged to reveal to the prosecutor any expert evidence they have obtained, but which they do not propose to use".[340] The Criminal Justice Act 2003, section 35, is intended to address this by introducing a new obligation on the defence:

"If the accused instructs a person with a view to his providing any expert opinion for possible use as evidence at the trial of the accused, he must give to the court and the prosecutor a notice specifying the person's name and address".

This requirement will come into force in April 2005. The CPS is also running a "Disclosure Project" that aims to raise awareness of the importance of disclosure and the role of experts in this process.[341]

SINGLE JOINT EXPERTS

149. Chief Constable David Coleman, former holder of the ACPO forensic science portfolio, when asked what could be done to minimise the problems associated with the adversarial nature of the UK criminal justice system, commented: "I'm tempted to say change the adversarial nature of the process".[342] David Coleman criticised the fact that the adversarial system "creates doubt and uncertainty in the mind of the jury when there is no need to do that".[343] One approach to this problem is the use of a single joint expert. Part 35 of the Civil Procedure Rules introduced in 1999 states that "Where two or more parties wish to submit expert evidence on a particular issue, the court may direct that the evidence on that issue is to be given by one expert only". Single joint experts are not used for criminal cases in the UK.

150. The single joint expert has been increasingly used in civil cases but it seems to be accepted that the use of a single joint expert is not suitable for all cases. Criticisms levelled at the approach include the fact that there is decreased opportunity for informal discussion of issues between the lawyer and the expert; and the fact that parties often decide to appoint a shadow expert to assess the case as well (thereby negating the cost savings associated with having a single expert).[344] Indeed, Mr Jani from the CPS indicated that if the defence did not agree with the expert appointed by the prosecution they may be entitled to have another appointed under the European Convention on Human Rights. Equally, the prosecution could seek their own experts if there were points of clarification required in the evidence of the expert appointed by the court.[345] Judge Thorpe was also of the view that it was rarely possible to use a single expert.[346] It has additionally been reported that some expert witnesses who have served as single joint experts in the civil courts have been reluctant to repeat the experience due to such factors as the increased workload and lack of a legal support team.[347]

PRE-TRIAL MEETINGS

151. Another practice from the civil courts that seems more likely to be adopted in the criminal courts is the use of pre-trial hearings to identify areas of agreement and disagreement between the experts for the prosecution and defence. These pleas and directions hearings do in fact happen already but Mr Jani from the CPS suggested that they were currently "not as effective as they should be" and Judge Thorpe said that his practice of holding a series of such hearings for serious cases was being criticised for "taking up court time".[348] According to the CPS, these constraints should be alleviated by the Criminal Case Management Framework and Criminal Procedure Rules 2005. Karen Squibb-Williams told us that "these reforms are designed to narrow the issues in each case and weed out some of the need to call experts at trial; both parties are expected to identify what elements of the Crown's case are: a. agreed/non-contentious (s9, CJA 1988); b. admitted (s10, CJA 1988), or; c. in issue".[349] Significantly, pre-trial meetings seem to have almost unanimous support, with the Bar Council opining that "if experts speak to each other and compare notes, calculations and workings, or even perhaps run experiments together, then the area of dispute will be diminished; costs will be lowered, and perhaps only one expert will be necessary after all".[350] We agree with this assessment.

152. Pre-trial meetings to identify areas of agreement and disagreement between experts must be held as a matter of routine; it is a false economy not to allow enough time for full discussion at this stage. We trust that the Criminal Case Management Framework and Criminal Procedure Rules 2005 will help to ensure that this happens in future but the Judicial Studies Board should ensure that its guidance emphasises the importance of this to the judiciary. Effective use of pre-trial meetings should reduce the potential for juries to become confused by unnecessary adversarial questioning. It should also avert the collapse of trials due to a known but previously undisclosed piece of evidence being put forward mid-trial that causes the expert on the other side to change their view.

SERVICES FOR THE DEFENCE

153. The CRFP posed the question in its memorandum: "Does the defence get as good a service as the prosecution?", telling us that this question was "central to the quality of justice".[351] In oral evidence, both the CRFP and the Forensic Science Society agreed that the defence now had, in theory at least, sufficient access to forensic services and experts. However, Professor Fraser, President of the Forensic Science Society, told us that the "fundamental barrier" to the defence getting as good a service as the prosecution was the "lack of knowledge of the importance or significance of the scientific evidence" and Professor Ebsworth, Chair of CRFP, pointed out that resources may still be a limitation.[352] The view of the Bar Council was that the defence "can get as good a service, but they sometimes have to push harder and overcome more bureaucratic hurdles".[353]

154. A forensic scientist appointed by the defence will usually not have any involvement in the case until much of the initial forensic analysis for the prosecution has been carried out. This means that the scientist for the defence will rarely see the evidence in its original condition. As Judge Thorpe said in oral evidence, "It is the Crown expert who has measured the marks on the road or looked at the child. The defence expert by and large is looking at work the Crown expert has done. He was not there, he did not see the child, he did not see the road himself".[354] The defence scientist also often has to collate their report within a much shorter timeframe than the prosecution scientist. On the other hand, the defence scientist has access to all the results of forensic tests carried out by the prosecution, even of these results are not used in the prosecution scientist's report. It is perhaps worth noting here that the Bar Council experience is that "In practice there are often difficulties in obtaining the fullest disclosure of the note and workings of experts relied on by the prosecution, or access to their database, if any".[355]

155. Historically, the defence did not have such ready access to, or make such extensive use of, forensic services as the prosecution (e.g. because material for forensic testing by the FSS had to be submitted through the police). The establishment of private sector providers and the changing status of the FSS have somewhat ameliorated that problem. Nonetheless, it is interesting that even now the proportion of FSS work comprising services for the defence is only 0.12%.[356] Mr Cooke offered one explanation for this, saying: "I will not use an FSS expert when I am defending because I believe—whether I am right or not is not the point—there is a corporate spirit that will mean an expert from the FSS will not go against the party line".[357] Judge Thorpe suggested Mr Cooke was not alone in this belief: "as a judge I very rarely see an expert for the defence who is an FSS man. It may be that they all share Graham's [Mr Cooke's] view".[358] Alternatively, this phenomenon may have more to do with that fact that, as noted by ACPO, "whatever one expert says, it is usually possible to find another expert who will disagree and often present an equally plausible explanation for a particular piece of evidence".[359] As a result, the jury may find itself in the very difficult position of having to evaluate the two alternative scientific interpretations.

156. The Bar Council raised another potential obstacle to be negotiated by the defence: "The Legal Services Commission often requires counsel's written advice before it will allow the necessary expenditure to instruct an expert for the defence […] The fee often has to be agreed before it is known how much work will need doing and what the costs involved in presenting the case in court might be".[360] Andrew Keogh of Tuckers Solicitors also expressed regret in a recent article in the New Law Journal at the failure to implement Lord Justice Auld's recommendation in his review of criminal courts that, where a judge thought an expert should be instructed, authorisation for funding should be automatic.[361] We urge the Legal Services Commission to implement Lord Justice Auld's recommendation to provide for automatic authorisation of funding where a judge is of the view that an expert should be instructed.

157. It is also interesting to note that a recent survey by the legal publisher Sweet and Maxwell found that 85% of expert witnesses are paid under £200 per hour, with 32% of all expert witnesses, and 68% of forensic experts, receiving less than £99 per hour. These figures need to be interpreted with regard to the fact that 81% of those expert witnesses had more than 10 years' experience of providing expert opinions to the courts, and roughly 25% had more than 20 years' experience.[362] This suggests that there is little foundation for the accusation occasionally levelled by some that expert witnesses routinely receive extortionate fees.[363]

Presentation of risk and probability

158. A particular area of difficulty in the interpretation of expert evidence by courts arises in the communication of risk and probability. The courts ultimately have to make a clear judgement about the case. By contrast, scientists can rarely give black and white answers and instead have to present a range of possibilities with, as far as possible, an indication of their relative probabilities. Professor Sir Alec Jeffreys expressed this as "a fundamental gulf between the philosophy of science and the philosophy of law".[364] If care is not exercised, the resulting tension can leave juries with a distorted understanding of the facts.

PRESENTATION OF DNA EVIDENCE

The prosecutor's fallacy

159. A common pitfall in the treatment of DNA evidence has been the so-called prosecutor's fallacy. It arises when the prosecution equates a statistical probability with the likelihood of guilt based on the statistical probability. For example, if the frequency of a particular DNA profile is one in a billion and there is a match between the DNA profile of the suspect and the DNA profile of a forensic sample from the crime scene, one way of presenting this would be: "the chance of obtaining this DNA profile if the DNA in the crime sample came from an individual other than the suspect is one in a billion". However, this is sometimes—inaccurately—presented in terms such as the following: "there is only a one in a billion chance the suspect is innocent". A more subtle, but equally misleading, variation would be: "the chance that the crime sample came from a person other than the suspect is one in a billion". In statistical terms, it is known as the "fallacy of the transposed conditional". It seems unreasonable to expect juries to recognise this trap, and experience has demonstrated that the fallacy can be overlooked by judges too.[365]

160. The judgement in R v Doheny and R v Adams (1996) is evidently designed to prevent scientists falling into this trap when presenting evidence to the court. It states:

"The scientist should not be asked his opinion on the likelihood that it was the defendant who left the crime stain, nor when giving evidence should he use terminology which may lead the jury to believe that he is expressing such an opinion".

In addition, the Court laid down three principles regarding the role of the expert. Firstly, the scientist should adduce the evidence of the DNA comparisons together with his calculations of the random occurrence ration. Secondly, the Crown should serve upon the defence details as to how the calculations have been carried out which are sufficient for the defence to scrutinise the basis of the calculations. Thirdly, the FSS should make available to a defence expert, if requested, the database upon which the calculations have been based.

161. Current FSS policy is to quote a match probability in a statement along the lines of:

366

The concept of a match probability has drawn criticism from some on the grounds that there is still too much potential for misinterpretation by the jury. Judge Anthony Thorpe has been a member of a working group of judges, lawyers and scientists set up to advise on a more appropriate way of communicating DNA evidence to the courts. The group has agreed a provisional form of words and is now hoping that the Court of Appeal will rule, when a suitable case is before them, that scientists should address DNA in the following way:

"The probability that an unknown person, unrelated to the defendant, would have the same profile as the crime sample is 1 in X [the relevant figure]".

This is also the wording favoured by Mr Cooke (who was part of the working group). In response to Mr Cooke's allegation that the current form of words used by the CPS is potentially misleading, Mr Jani, on behalf of the CPS, has "suggested that the public be consulted in a scientific poll to assess the validity of this claim".[367]

162. It is apparent that there is still a great deal of confusion regarding the best approaches for the presentation of statistical evidence to juries, even for DNA evidence which has now become a routine part of many criminal investigations. We are of the view that there is significant room for improvement in the way that statistical evidence, including risks and probabilities, is presented to juries. In order for this to occur, there needs to be a better understanding of the forms of wording and presentation that are easiest to understand, and least misleading, to members of the general public. We do not make a judgement about which form of wording is most apposite for the presentation of DNA evidence but recommend that the decision be informed by research. The training of judges and lawyers in the relevant areas of statistics, and of experts in the communication of this type of evidence, could also make an important contribution to improving the treatment of risk and probability in court, as discussed further in paragraphs 177-182.

COMMUNICATION BETWEEN SCIENTISTS AND LEGAL PROFESSION

163. The resolution of the conflicts and uncertainties surrounding the presentation of statistical and scientific evidence would be greatly facilitated by the existence of effective mechanisms to encourage interchange between scientists and lawyers and judges. Indeed, channels of communication between forensic experts and the legal profession are essential to give early warning of the existence of such problems. It was therefore troubling to hear Graham Cooke, a barrister, complaining that feedback of scientists and experts to the courts was "non-existent".[368] The Bar Council's assertion that "there are frequent opportunities, in conference, at seminars, and at lectures for members of the Bar and the judiciary to meet with professionals in other fields" and observation that "experts are invited to dine with the judges at the Inns of Court" were somewhat feeble and provided little reassurance.[369] The CPS noted that "the Office for Criminal Justice Reform has been extensively involved in discussions with the judiciary", and we are, of course, aware of the ad hoc group led by Judge Thorpe to review the wording used to present DNA evidence.[370] The absence of formal and permanent channels for forensic scientists and experts to give feedback on their courtroom experiences seems to us to represent a serious flaw in the criminal justice system. We recommend that the Home Office establish a forum for Science and the Law, which meets at least every six months. If the recommendation to set up a Forensic Science Advisory Council is adopted, the forum should be subsumed into this body. The Science and the Law Forum could play a vital role in drawing and disseminating lessons from the handling of scientific evidence in individual cases. It could also assist in considering how best to deal with evidence emerging from novel technologies (see paragraph 171 for further discussion).

Juries

164. It is not unreasonable to expect that juries may find it difficult to interpret the significance of some highly technical evidence. Yet jury research is currently prohibited in this country, making it difficult to assess conclusively the impact of complexity on juries. At present, section 8 of the Contempt of Court Act 1981 and the related common law assures the confidentiality of a jury's deliberations and precludes research into these deliberations. Limited research is permitted regarding the processes of selecting, informing and supporting jurors during their service, but none has been published that pertains specifically to forensic, or other expert, evidence. Judge Thorpe commented in oral evidence that the status quo means that "The plain fact is that none of us knows why a jury comes to the decision it does, whether it is complexity or not".[371]

165. The Home Office has recently published the results of a research project addressing the attitudes of jurors who have recently completed jury service. The study looked at "jurors' perceptions, understanding, confidence and satisfaction as a result of their service".[372] The study found that most respondents had a more positive view of the jury trial system after completing their service than they had before. While the "main impediment to understanding proceedings was the use of legal terminology […] jurors also felt that evidence could sometimes be presented more clearly".[373] However, the research did not address the impact of complexity, and Penny Darbyshire et al have also commented that "research which simply asks jurors, for instance, whether they understood instructions or evidence" is of "questionable value" since the fact that jurors claim to have understood something does not mean that they actually did understand it.[374] Jury research is permitted in some other jurisdictions and mock trials have also been used for research purposes, although this approach obviously has its limitations too. Darbyshire et al produced a paper entitled, What can the English Legal System Learn from Jury Research Published up to 2001, which reviewed a large body of the evidence available from research both in the UK and elsewhere, as input to the Auld review.[375] The paper cites various pieces of research relating to the credibility of expert witnesses. Amongst the findings noted are that jurors appear to evaluate credibility "by judging the status of the source combined with a subjective judgement of their knowledge and an assessment of their presentation"; and that, "when cross-examining expert witnesses, any questioning of that witness's reputation instantly damages their credibility, even when the accusations are without foundation".[376]

166. Further to a recommendation by the Home Affairs Select Committee that the Government should "consider the merits of repealing section 8 of the Contempt of Court Act 1981, in order to permit meaningful research into how the jury system operates", the Secretary of State for Constitutional Affairs has launched a public consultation on whether the restrictions on jury research should be lifted.[377]^,[378] Both Judge Thorpe and Mr Cooke, a barrister, told us in oral evidence that they were wholly in favour of permitting jury research.[379] It is also of note that the Royal Commission on Criminal Justice recommended in 1993 that section 8 be amended to allow properly authorised research into the way in which juries reach their verdicts. By contrast, Lord Justice Auld recommended in his 2001 review of the criminal courts that there be no amendment of section 8 to allow research into jurors' deliberations.[380] Jury research is vital to understand how juries cope with highly complex forensic evidence. Jury research would also be instructive for understanding differences in the way that jurors respond to oral and written reports by experts, and how easy they find interpretation of these reports. We recommend that section 8 of the Contempt of Court Act be amended to permit research into jurors' deliberations.

167. The 1986 "Roskill Report" of the Fraud Trials Committee noted that the Committee was disadvantaged in its efforts to determine whether or not jurors could understand the technical evidence and complex issues in fraud trials by the fact that they were not allowed to discuss this topic with the jurors in such trials.[381] Nevertheless, the Roskill Report recommended that in serious fraud cases, jury trial be replaced by a Fraud Trials Tribunal, consisting of a judge and a small number of specially qualified lay members.[382] This recommendation was not adopted by the Government at that time, but Part 7 of 2003 Criminal Justice Act allows for trials on indictment without a jury on the application of the prosecution in some fraud cases (Part 7 is not force yet). Jury trial is perceived by many to be a "hallowed democratic institution" that serves as the "best and fairest means available" of arriving at a judgement.[383]^,[384] However, there are already instances in which this principle is rightly departed from. Advancements in science and technology impact on both the techniques used by criminals and the approaches employed in fighting and detecting crime. It is, therefore, highly likely that the number of cases which depend on complex forensic evidence will increase. This is already happening with regard to digital evidence. The Home Office should undertake research to test whether there would be value in extending the arrangements for complex fraud trials to be tried without a jury to other serious cases that rest on highly complex scientific evidence. This research must also address public attitudes towards this possibility.

Scrutiny of expert evidence

SYSTEMS FAILURE

168. The prosecution of Sally Clark for murdering her two babies partly relied on an assertion by an expert witness, Professor Sir Roy Meadow, that the probability of the two deaths having been incidences of cot death (also known as Sudden Infant Death Syndrome or Sudden Unexplained Death in Infancy) was 1 in 73 million. Aside from the fact that the calculation underlying this probability is incorrect, it has also been pointed out that this calculation was never compared with an estimate of the probability that the two deaths were the result of a double murder.[385] Sir Roy was a paediatrician with no specific expertise in statistics and there were no other witnesses at the trial with qualifications in statistics. The court at Sally Clark's first appeal refused to hear oral testimony from two statistical expert witnesses, on the grounds that it was "hardly rocket science". The court ultimately concluded that "any error in the way in which statistical evidence was treated at trial was of minimal significance" and dismissed the first appeal.[386] The second—successful—appeal revolved around medical evidence that had previously not been disclosed by the pathologist, although the court also thought that the misleading impact of the statistical evidence at Sally Clark's first trial would in itself have been sufficient ground for declaring the conviction unsafe.[387]

169. Most informed observers seem to accept that Professor Sir Roy Meadow gave his evidence in good faith, no matter how erroneous it turned out to be. Yet he has been publicly vilified through the extensive media reports that focussed on his role in the miscarriages of justice in the Clark and Cannings cases.[388] By contrast, little attention was given, at least in public, to the lawyers and judges involved, who may have been able to prevent the miscarriage of justice from being carried out, but failed to do so. In oral evidence to this inquiry, Professor Sir Alec Jeffreys expressed his amazement that the flaws in Professor Sir Roy Meadow's statistical evidence were "not tracked right at the beginning", describing it as "a failure not only of the experts but also of the courts".[389]

170. The treatment of this case has had many wider ramifications, one of which is the increasing reluctance of experts to risk their reputations by appearing as expert witnesses. There is anecdotal evidence that it is now even more difficult to find experts for child protection cases. Additionally, the Royal College of Paediatrics and Child Health recently found that 29% of doctors who had been the subject of complaints about their work said that their willingness to work in child protection had been affected.[390] This was not dependent on the outcome of the complaint, the vast majority of which were either dropped or not upheld following investigation.[391] Expert witnesses have been penalised far more publicly than the judge or lawyers in cases where expert evidence has been called into question. These cases represent a systems failure. Focussing criticism on the expert has a detrimental effect on the willingness of other experts to serve as witnesses and detracts attention from the flaws in the court process and legal system which, if addressed, could help to prevent future miscarriages of justice.

ADMISSIBILITY OF EXPERT EVIDENCE

171. Establishing the validity of new scientific techniques or theories, and the basis for their interpretation, is essential before evidence derived from them can be used in court. It is not always straightforward for judges to decide whether to admit forensic evidence. It is worth noting, for example, in the last year the Court of Appeal has considered ear-print, lip-reading and facial mapping evidence in conjunction with criminal cases.[392] In addition, polygraphs, commonly known as "lie detectors", are currently used in criminal investigations in many countries including Belgium, Canada, Israel, Japan and the USA, despite evidence that the error rate of such tests can be significant.[393] Future improvements in polygraphic techniques could prompt the courts in the UK to reconsider whether to admit evidence derived from these techniques.

172. Most states in the US follow well defined procedures to establish whether evidence from a particular scientific technique should be admitted. According to the Frye test (named after the defendant in a murder case in 1923), courts can only admit evidence derived from novel scientific techniques once the technique has gained general acceptance in the scientific community to which it belongs. The test entails first identifying the field in which the theory underlying the new technique falls, and then determining whether the principle of the technique is widely accepted by most members in this field.[394] Most states now also apply the Daubert test to scientific or technical expert evidence.[395] The Daubert principles require expert testimony to be tested against four criteria:

Whether the theory or technique can be (and has) been tested;
Whether the theory or technique has been subjected to peer review and publications;
In the case of a particular technique, what the known or potential rate of error is or has been; and
Whether the evidence has gained widespread acceptance within the scientific community.[396]

Dr Chris Pamplin, editor of the UK Register of Expert Witnesses, has argued that "As a result of Daubert, expert evidence in the US is likely to come under close scrutiny at an earlier stage that in UK proceedings", averring that "it is time for our courts to formulate similar rules. They might do better than the American model, but they could, at least, do no worse".[397]

173. Professor Sir Alec Jeffreys also expressed his concern about the lack of established protocol in this country for deciding whether to admit scientific evidence.[398] ACPO is similarly unhappy with the current situation: "To a large extent we are at the mercy of the criminal justice system as we have no agreed method of getting new techniques validated", and refers to the US Frye and Daubert hearings as "an interesting development".[399] We are aware that dogged adherence to criteria such as those commonly used in the US could stymie the use of less mainstream, but nonetheless valid, expert evidence. However, the idea of an objective, clearly defined test to establish whether a theory or technique is sufficiently robust and evidence-based to merit admission in court is highly attractive. The absence of an agreed protocol for the validation of scientific techniques prior to their being admitted in court is entirely unsatisfactory. Judges are not well-placed to determine scientific validity without input from scientists. We recommend that one of the first tasks of the Forensic Science Advisory Council be to develop a "gate-keeping" test for expert evidence. This should be done in partnership with judges, scientists and other key players in the criminal justice system, and should build on the US Daubert test. The development of such a test would complement the increasing emphasis on pre-trial hearings in England and Wales discussed in paragraph 151.

EARLY WARNING SYSTEM

174. The legal profession seems to be largely content that the adversarial system in the UK offers adequate opportunities for the testing of expert evidence. The Bar Council, for instance, told us:

"scrutiny takes place because the adversarial system provides for the independent challenge of the prosecution view. This is an important safeguard. The second line of protection is the defence advocate who can be expected to prevent improper evidence or unsupported assertion. A third line is the judge who is expected to do the same. In our view these safeguards in practice have proved sufficient albeit no system is perfect".[

400

The Home Office also asserted that the new Criminal Case Management Framework and Criminal Procedure Rules will help to "curb some of the extravagancies of the adversarial system".[401] Staged reporting, as laid out in the Prosecution Team DNA Guidance, will also reduce the number of cases in which the expert is required to give full evidential statements and appear in court: the Crown will rely on an abbreviated statement from the forensic scientist where the contents are not in issue.[402] However, this is initially being restricted to cases involving DNA.

175. Despite these developments, the Metropolitan Police Service highlighted in its memorandum "the need for clarity in processes to deal with expert evidence that is called into question" and ACPO identified a "need for the Criminal Justice system to develop a consistent and clearly understood quality control and remedial process to cater for these eventualities".[403] Gary Pugh, Director of Forensic Services for the MPS, expanded on this in oral evidence, telling us there should be "an early warning system" to raise the alarm when expert evidence has been called to into question, for example by the expert's peers.[404] ACPO further explained that it "would welcome an open system where professionals within the investigative process and criminal justice process: Senior Investigating Officers, Prosecutors, Counsel and Judges, or even members of the public, can report concerns to some central point".[405] Provision would then need to be made for rapid validation of the concerns and, where necessary, disciplinary action against the expert and a review of their current and previous cases. ACPO suggested that the CRFP, in partnership with the law enforcement agencies and the legal professions, might be best placed to fulfil this role, but noted that this would be more effective if CRFP registration was mandatory.[406] The stance of the Bar Council, Home Office and CPS that the adversarial system provides sufficient safeguards so as to obviate the need for independent scrutiny of expert evidence is complacent and at odds with the views of the police. We accept that the criminal justice reforms that are being introduced may offer some improvements to the status quo in due course, although it seems that much will still be left to the discretion of the judge.

176. We recognise that the number of miscarriages of justice associated with flawed expert evidence is unlikely to be high, and the legal system as it stands should enable miscarriages in serious cases to come to light eventually. Nevertheless, there is no way of knowing the actual number of cases that have been adversely affected by problems with expert testimony or its interpretation, particularly more minor cases which are unlikely to have been the subject of an appeal. Even if problems are rare, the human cost and damage to public confidence in the criminal justice system caused by the miscarriages of justice associated with flawed expert evidence that have already occurred must be taken into account. Moreover, we believe that steps could be taken that would reduce the potential for such miscarriages of justices to occur. We recommend that a Scientific Review Committee be established within the Criminal Cases Review Commission. This Committee would be charged with handling complaints about expert evidence and, even where there are no grounds for an appeal, should work closely with the main forensic providers and the CRFP to address any problems identified with an expert's conduct. The Scientific Review Committee should also work closely with the Forensic Science Advisory Council once it is set up.

Training of judges and lawyers in forensic evidence

177. Brian Thompson, secretary of the Expert Witness Institute, has pointed out that the success of the adversarial system in ensuring that expert witness testimony stands up to scrutiny depends on the proficiency of the lawyers involved, commenting that "There is a real danger that if lawyers do not understand expert evidence then it will not be properly tested".[407] In the course of this inquiry, we heard repeated calls for better training of judges and the legal profession. We were particularly pleased to hear the Minister acknowledging that "it is an area we need to develop".[408]

LAWYERS

178. Dr Ann Priston, Vice-President of the Forensic Science Society, told us in oral evidence of the "tremendous lacking in training [in forensic evidence] for lawyers at all levels" and said that "training should be part of a lawyer's training right at the very outset, from pupil barrister upwards".[409] Graham Cooke, a barrister, also remarked: "There is a real problem with DNA evidence […] the Bar is taught nothing. It relies upon its general principle of doing the right thing, which is that in any area of law you should check your case and look up the authorities […] the Bar is a disgrace in this".[410]

179. The Bar Council, unsurprisingly, did not accept this view, telling us that "the Bar is generally well skilled in this area", but it also admitted that "training [in forensic evidence] is not delivered to everyone, is not mandatory, and depends largely on the professionalism of the advocate".[411] The Bar Council additionally noted that "All members of the Bar, however experienced, are now expected to receive a minimum period of 12 hours continuing education each year in order to acquire an annual practising certificate" and "Most do more than that anyway".[412]

180. The CPS also does not give its lawyers any mandatory training in the understanding and presentation of forensic evidence. However, all Chief Crown Prosecutors "received a brief awareness raising session (of the new Prosecution Team DNA Guidance)" and the CPS, like the Bar Council, drew our attention to the requirement for lawyers to undertake continuing professional development.[413] In addition, guidance is made available to the prosecution team on topics such as the presentation of DNA evidence. The CPS sent us a number of examples of the available guidance, produced by the CPS and others such as the FSS and ACPO. While we have no particular complaints about the quality of the guidance available to lawyers on the understanding and presentation of forensic evidence, it is of great concern that there is currently no mandatory training for lawyers in this area. In view of the increasingly important role played by DNA and other forensic evidence in criminal investigations, it is wholly inadequate to rely on the interest and self-motivation of the legal profession to take advantage of the training on offer. We recommend that the Bar make a minimum level of training and continuing professional development in forensic evidence compulsory.

JUDGES

181. We were presented with a similarly disturbing picture of the levels of training given to judges. Judge Anthony Thorpe, Resident Judge at Chichester Crown Court, agreed with Mr Cooke's assessment that "When it comes to DNA I am afraid […] senior judges are innumerate".[414] Judge Thorpe explained that "for most of the judges, apart from the lectures which you get at the seminars run by the Judicial Studies Board, it is probably on-the-job training".[415] Dr Priston has herself run courses for circuit judges and said that, in her experience, "it is hard to get them [the judges] to come but, when they do come, they love it and they all say, 'We had no idea of the detail'".[416] It is also of interest that the joint report from the Royal College of Pathologists and the Royal College of Paediatrics and Child Health recommended that "Establishing the expertise of witnesses should be included in judicial training".[417]

182. The Government-funded Judicial Studies Board is responsible for delivering training material and courses to judges and magistrates. All circuit judges receive formal residential training for four days every three years (continuation seminars), as well as attending an annual one day session. Criminal continuation seminars always include "some input from an expert", whether from the medical, DNA or mental illness specialties.[418] In addition, judges authorised to try serious sexual offences cases receive specialist training which touches on issues of expert evidence. Both Judge Thorpe and the Bar Council pointed out that any increase in the amount of training given to judges must be considered in the context of the heavy costs associated with releasing judges from the courts. Improving the training given to lawyers in the understanding and presentation of forensic evidence should eventually produce judges with a more solid understanding of these topics. However, in light of the rapid pace of scientific progress, we recommend that judges be given an annual update on scientific developments of relevance to the courts. The introduction of mechanisms to enable scientists and experts to give feedback on their experience in court (see paragraphs 163 and 176) should enable production of better targeted training material, and the introduction of Daubert-style tests should also help to ensure that judges have more scientific input when making decisions about whether to admit expert evidence.

SPECIALIST JUDGES AND LAWYERS

183. It is unrealistic to expect every barrister and judge to acquire a specialist's understanding of all the many elements of forensic science. It is more important that a good grounding in the most commonly encountered areas, such as DNA evidence, becomes a routine component of training for the legal profession. Nevertheless, there will be a minority of cases where the ability of the lawyer or judge to fully comprehend complex scientific or technical evidence could have a major bearing on the case. We asked the CPS whether it would support the development of a group of barristers and solicitors with specialist expertise. The CPS rightly pointed out that "Evidence (e.g. digital & DNA) is now no longer limited to serious crime, but is used throughout the criminal law, including volume crimes".[419] The CPS used this to justify the assertion that "To support the creation of a narrow group of specialists would be counterproductive to the need for the widespread knowledge and skills of all prosecutors".[420] The Bar Council also expressed concern that direct training of judges in particular specialisms "would open them up to the criticism that they might be substituting their un-examinable views for the views of the expert before them. This would detract from the concept of open justice".[421]

184. We agree with the CPS that it is impractical and undesirable to have pools of expert lawyers for every potential speciality, and with the Bar Council that judges (or lawyers) should not usurp the role of witnesses. Nonetheless, we believe that the concept of specialist judges and lawyers for cases relying on complex forensic evidence has not been given sufficient consideration. There are certain areas, such as the digital evidence specialities, which are becoming critical in a growing number of cases. Furthermore, the potential complexity of such cases is escalating all the time. A spin off benefit to offering specialised training to lawyers would be an overall increase in the number of scientifically-literate lawyers (and thus, in the fullness of time, judges). We recommend that the Home Office issue a consultation on the development of a cadre of lawyers and judges with specialist understanding of specific areas of forensic evidence. An additional benefit to this would be the creation of a small group of judges and prosecution and defence lawyers with the ability and current knowledge to act as mentors to their peers when required. The possibility of trials without jury is raised in paragraph 167. Whilst specialist lawyers and judges could obviously play a role in that system, they could equally make a useful contribution to jury trials.

306 R v Cannings [2004] 1 WLR 2607, http://www.bailii.org/ew/cases/EWCA/Crim/toc-C.html Back

307 Ev 106 Back

308 Ev 106 Back

309 Ev 107-108 and memorandum from Alan Kershaw [not printed] Back

310 Ev 108 Back

311 Ev 106 Back

312 Ev 107 Back

313 Ev 107 Back

314 Q 221 Back

315 e.g. Ev 166 Back

316 Letter from the Prime Minister to Judge Anthony Thorpe [not printed] Back

317 Ev 100, Ev 131 Back