Introduction
The increasing number of sophisticated cases before courts makes expert evidence an integral part of today’s legal systems. Expert evidence can be defined as any evidence that calls for an expert opinion to be helpful to the court. A person that renders that opinion is referred to as an expert witness. These witnesses play a critical role in helping courts administer justice to parties by expressing themselves on issues beyond the general knowledge of judicial officers. However, until the early 18th century, expert evidence was alien to the legal system in England and Wales. It was first used in the celebrated case of Folkes v Chadd, [1]where the court allowed a famous scientist, Mr Smeaton, to give his opinion on specific facts of the case.[2] Admitting the expert evidence, Lord Mansfield stated thus, ‘an expert opinion after receiving the knowledge of facts is admissible in the court of law if the witness has substantial knowledge and vast experience in that particular field related to the case.'[3] Critical in his judgement were the terms ‘after receiving the knowledge of the facts.’ The phrase implies that merely having expertise and experience in a field did not make one a competent expert witness under common law. One needed to demonstrate adequate knowledge of facts relevant to the matter in question. A similar position was held in the case of R v Turner, where the court stated that consideration or reference to irrelevant facts about a case renders an expert’s opinion irrelevant and inadmissible.[4] Since then, courts have played a critical role in setting and defining the jurisprudence of expert evidence in England and Wales. They have created the principles of reliability, expertise, and assistance of expert witnesses in court processes.[5] Therefore, the initial approach to legal regulation of expert evidence in England and Wales was mainly laissez-faire, with reliance on judicial precedents. As characteristic of judicial precedents, the approach faced challenges, primarily resulting from the uncertain rules of testing the admissibility of the expert evidence.[6] The challenges threatened the parties’ right to access justice, and a remedy was needed. As will be seen later in this discussion, the current approach has remedied several challenges of the earlier approaches. Presently, courts of England and Wales draw their guidance on expert evidence from both statutory and common law principles.
The Present Approach to Legal Regulation of Expert Evidence
For about 150 years, expert evidence remained in the purview of the courts. During that time, precedents shaped courts’ approaches to determining expert witnesses’ qualifications, experience, obligations, and admissibility of their opinions. The approach was marred with uncertainties and inconsistencies as judges and juries interpreted precedents differently.[7].
Various groups, including commissions and committees, raised concerns about how courts handled expert evidence. They highlighted the need for a harmonized and well-regulated approach to admitting expert evidence.[8] For instance, the House of Commons Science and Technology Committee of 2005 averred that courts admitted expert opinions more readily without sufficient scrutiny.[9] The Law Commission echoed a similar position in their 2009 consultation paper, The Admissibility of Expert Evidence in Criminal Proceedings in England and Wales.[10] The commission later published a report in 2011, which recommended the adoption of a new statutory framework to govern the admissibility of expert evidence in proceedings before courts.[11] The regime was to set a straightforward statutory reliability test and codify and refine the common law principles touching on expert witnesses’ impartiality, expertise, and assistance in criminal proceedings.[12] The immediate result of the above developments was the Criminal Practice Directions 19A (CrimPD 19A) and later part 19 of Criminal Procedure Rule 2020. Presently, the admissibility of expert evidence is governed by both common law principles and statutory guidelines.
The Place of Common Law Principles
England and Wales operate under a common law legal system. In such a system, case laws form a critical part of their legal proceedings, and the decisions and principles of higher courts bind lower courts.[13] The place of common law in handling expert evidence is recognized under CrimPD 19A. In common law, the admissibility of expert evidence depends on factors such as the possible assistance of the evidence to the court, the expert’s expertise, and the reliability of their evidence. Perhaps more explicit guidance was given by Thomas LJ in the case of R v Reed & Reed [2009].[14] The learned judge addressed himself thus;
‘First, expert evidence of a scientific nature is not admissible where the scientific basis on which it is advanced is insufficiently reliable for it to be put before the jury… Second, even if the scientific basis is sufficiently reliable, the evidence is not admissible unless it is within the scope of evidence an expert can properly give… Third, unless the admissibility is challenged, the judge will admit that evidence.’[15]
For expert opinion to be admissible in criminal proceedings, it must be of assistance to the court. Lord Mansfield first noted the help of experts in criminal proceedings in Folkes v Chadd (supra). The judge explained that some forms of evidence are better given by experts. For instance, experts help judicial officers understand complex issues, such as scientific principles. Nonetheless, expert evidence is inadmissible unless it offers necessary assistance to the court. In R v Turner (supra), the court dismissed evidence of a psychiatrist who attempted to describe how a normal person would behave before the court.[16] The above was seen to offer no assistance to the court as it was a matter of judicial notice. Whether a piece of evidence is of assistance to the court is a matter of fact and must be determined on a case-to-case basis.[17] The test of assistance is arguably the first that must be satisfied.
An expert witness must have relevant expertise in a given field for their evidence to be admissible. A person is said to have expertise in an area if they can demonstrate that through study or experience, they have adequate knowledge of the field.[18] Arguably, the courts set this threshold to ensure that only qualified persons get the opportunity to contribute to the proceedings. Importantly, assessing the expertise ensures that experts refrain from giving an opinion on matters outside their knowledge and expertise.[19] The above was the case in R v Clarke Morabir[20], where the court dismissed evidence of an expert in bones who had attempted to explain the cause of a victim’s death. This approach to admitting expert evidence in court is often challenging, especially concerning experts who gain knowledge through experience or informal methods.[21] For instance, courts took different stances on two similar cases. In the case of R v Hodges (2003), the courts admitted the evidence of a police officer on a supply of heroin based on the fact that the officer had had several years investigating drug offences.[22] However, in R v Ely Magistrates’ Court [2008][23], the court dismissed evidence of a defence witness, arguing that the witness lacked the necessary expertise to testify on the matter because he had not taken any of the approved schools on speed detection devices.[24] As noted above, common law principles can be confusing in some cases.
Another critical principle under common law that helps courts regulate expert evidence is reliability. Before a witness or his evidence is allowed in a criminal proceeding, the parties must demonstrate that the evidence has a sufficiently reliable scientific basis.[25] Unfortunately, there are a limited number of case laws examining what level of reliability is sufficient. As a result, confusions arise as judges and judicial officers continue to give conflicting and varying holdings to this effect. For instance, the decision in the case of R v T (2010)[26] has been criticized for having ignored critical pieces of evidence in employing what it defined as the likelihood ratio approach.[27] The above uncertainties resulted in the concept of ‘potentially safely reliable,’ where judicial officers look no further than the fact that an expert’s opinion that can safely be held reliable is admissible.[28] In determining the reliability of an expert opinion, the court will also look at the technique used by the expert in arriving at the opinion.[29] However, the courts are invited to look beyond the fact that a scientific process was involved. They must examine whether the scientific approaches adopted are reliable in making relevant inferences. In the case of Re NL (Appeal: Interim Care Order: Facts and Reasons) [2014],[30] the court raised concerns with the evidence of Dr Van Rooyen. In this case, the doctor conducted an incomplete procedure in his analysis, and Pauffley J dismissed his evidence for being unreliable.[31] The courts must also disallow manipulated pieces of evidence. Such was the case in Re F [2016] EWHC 2149, where Hayden J. ruled that any evidence compromising the fairness of a hearing process must be held unreliable and hence inadmissible in the common law.[32]
New case laws are emerging, with judges and judicial officers seeking to refine the various principles regarding the admissibility of expert evidence. However, it must be appreciated that the amendments to the Criminal Procedure Rules and Criminal Practice Directions that began in 2015 have eased the process.
The place of statutory provisions
Statutory regulation of expert witnesses took a sharp shift after the debates resulting from the Law Commission’s report, which proposed numerous regulatory changes to using expert evidence in courts. As already indicated, pre-2015 legislation offered little guidance to courts as to the admissibility of expert witness evidence. Nonetheless, it must be acknowledged that the place of expert witness evidence in courts was protected under section 30 of the Criminal Justice Act of 1988. Even as such, the regulation of expert witnesses was in the ambit of courts as guided by case laws.[33] Therefore, the introduction of Criminal Practice Direction 19A in 2015 marked a significant step towards a solemnized regulatory approach to expert evidence in England and Wales.[34] In addition to appreciating the place of common law principles, the directions lay clear guidelines upon which courts can rely in handling expert evidence.
The introduction of Criminal Practice Directives 19A sought to remedy the challenge of inconsistencies that arose in common law with regard to assessing the admissibility of expert witnesses and their evidence. To that effect, the directions contained several rules that governed the use of expert evidence in court. They also implored judicial officers to astutely identify potential flaws in expert opinions, such as overreliance on hypothesis, unjustified assumptions, and use of flawed data.[35] The directions also allowed the jury to weigh and decide on the opposing views regarding expert evidence. The above is often regarded as an approach that ensures the court is not deprived of the grasp of evidence that would otherwise be useful.[36] The directives of 2015 laid the necessary foundation for the adoption of part 19 of Criminal Procedure Rules 2020[37], which provided a clearer approach to the duties and obligations of expert witnesses in criminal proceedings. The consolidation of rules relating to expert evidence is a positive step towards ensuring convenience in criminal proceedings.
Part 19 of the Criminal Procedure Rules 2020 provides an extensive overview of the approaches courts can adopt in admitting and assessing the admissibility of expert evidence. The part applies when a party seeks to introduce expert evidence in court.[38] Rule 19.2 outlines the various duties that such experts owe courts. Some of these include the duty to help the court achieve its overriding objectives by giving unbiased evidence inspired by expertise.[39] The rule also expects the witness to comply with court orders and communicate clearly where necessary. Such communications may include indicating to the court any delay that may ensue when preparing and presenting the evidence. The above rule seems to have a rooting in the 2014 case of R v Reynolds, R v Rosser[40]where the Court of Appeal highlighted the need for a more explicit guideline on the time within which an expert can prepare evidence.
According to Rule 19.3, expert evidence can be introduced either as a fact or an opinion. Arguably, the rule can be said to be a positive response to the second and third recommendations of the Law Commission’s 2011 report. These rules set specific guidelines for the admissibility of such facts and opinions. Rule 19.4, for instance, specifies that an expert report introduced as an opinion must highlight the expert’s qualifications, relevant experience, and accreditation.[41] The above provision is a departure from the common law principle that expected these to be explained during the proceedings. The report must also depict the expert’s reliability and expertise by showing the basis of their opinions. Interestingly, rule 19.9 allows experts to withhold some information from other parties. However, the application can only be made in the public interest and according to privacy and confidentiality regulations.
Despite marking significant improvements to the legal regulation of expert evidence in England and Wales, the statutory provisions failed to resolve some issues. Positively, they harmonized the laws relating to expert evidence and increased convenience. However, they failed to address some historical challenges of uncertainty. For instance, there still needs to be a clear definition of what amounts to sufficiently reliable evidence. Even courts in many common law jurisdictions still need help dealing with this challenge.[42] The need to remedy this challenge came out strongly in the Law Commission’s report and subsequent Draft Bill of 2011, but the Department of Justice failed to address it.[43] Instead, it responded negatively by citing the high cost of fully implementing the recommendation.[44] The legal system should learn from the experiences of the United States, which solved this problem by adopting the Federal Rules of Evidence early in the 1990s after the celebrated case of Daubert v. Merrell Dow Pharmaceuticals Inc.[45] In the above case, the United States Supreme Court set the basic rules for admitting expert evidence in courts. Congress acted fast to incorporate the guidelines with more clarity in their legislation.There is a need for such an approach in the country.
Conclusion
The upshot of this discussion is that legal regulation of Expert witnesses in England and Wales is governed primarily by principles of common laws and specific statutory regulations. The common law principles stemmed from the celebrated case of Folkes v Chadd (supra) and have developed over time. For expert evidence to be admissible in common law, it must be reliable, useful to the court, and given by a person with relevant expertise in the field. The blanket application of the above principles raised concerns, with litigants citing inconsistencies and injustices. The above was also captured in Law Commission studies conducted between 2009 and 2011. The commission’s recommendations shaped the course of amendments to the criminal procedures and directions. Currently, the Criminal Procedure Rules of 2020 are the courts’ primary point of reference in handling expert evidence. However, the regulation, as it stands, does not handle the test of the reliability of expert evidence. This paper finds the need for an amendment to provide a clear framework for assessing the reliability of expert witness evidence. That way, courts in England and Wales will find it easy to render justice.
BIBLIOGRAPHY
Cases
Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579 (1993)
Folkes v Chadd (1782) 3 Doug KB 157
R (Doughty) v Ely Magistrates’ Court[2008] EWHC 522
R v Clarke Morabir [2013]EWCA Crim. 162
R v Hodges [2003] EWCA Crim. 290
R v Reed & Reed [2009] EWCA Crim. 2698
R v Reynolds, R v Rosser [2014] EWCA Crim 2205
R v T [2010] EWCA Crim 2439
R v Turner (1975) 1 All ER 70
R v Riat [2012] EWCA Crim 1509, [2013] 1 WLR 2592 33
Re NL (Appeal: Interim Care Order: Facts and Reasons) [2014] 1 FLR 1384
Statutory Rules
Criminal Justice Act 1988 c 33
Criminal Practice Directions, 2015
Criminal Procedure Rules, 2020 No. 759 (L. 19)
Reports
Forensic Science on Trial, Seventh Report (2004–2005) HC 96-1
Law Commission Consultation Paper No. 190 (2009)
Law Commission, ‘Expert evidence in criminal proceedings in England and Wales,’ (21 March 2011), Law Com No 325
Journal Articles
Dainow J, ‘The Civil Law and the Common Law: Some Points of Comparison’ (1966) 15:3 The American Journal of Comparative Law 419–35
Das S, ‘A Look into the Treatment of Expert Witness Evidence in English Law in the Light of the 21st Century.’ (2021) IPleaders
Elton J, ‘Expert Evidence, Juries and the Search for Truth: A Case Study Analysis.’ (DPhil Dissertation, De Montfort University 2019)
Fisher BAJ, ‘A new challenge for expert witnesses relying on subjective information.’ (2017) Forensic Sci Res. 2(3):113-114
Freckleton I, Goodman J, Horan J and McKimmie B, ‘Expert Evidence and Criminal Jury Trials’ (Oxford University Press New York, 2016) 1.09
Makanje GD, ‘The Admissibility of Expert Evidence in Criminal Proceedings in Malawi: A Call for Reliability Safeguards’ (2023) 67 Journal of African Law 117
Martire, KA and Edmond G, ‘Rethinking Expert Opinion Evidence’ (2017) 40 Melbourne University Law Review 967
Michael S and Jackson A, ‘Expert Evidence in Criminal Proceedings.’ (2016) The Journal of Criminal Law
Milroy CM, ‘A Brief History of the Expert Witness.’ (2017) 7 Academic Forensic Pathol. 3 516-526
Morrison GS, ‘The Likelihood-Ratio Framework and Forensic Evidence in Court: A Response to R v T’ (2012) 16 International Journal of Evidence and Proof 1
Segal S, ‘When Expert Evidence Goes Wrong: Lessons from Case Laws’ (2018) Experts in the Family Justice System (EFJS) Committee
Ward T, ‘‘A new and more rigorous approach’ to expert evidence in England and Wales?’ (2015) The International Journal of Evidence & Proof
Ward T, ‘Expert evidence and the Law Commission: implementation without legislation?’ (2018)
Ward T, ‘Explaining and trusting expert evidence: What is a ‘sufficiently reliable scientific basis’?’ (2020) The International Journal of Evidence & Proof
[1]Folkes v Chadd (1782) 3 Doug KB 157.
[2] Christopher M Milroy, ‘A Brief History of the Expert Witness.’ (2017) Academic Forensic Pathol. 7(4), 516-526.
[3]Folkes (n1).
[4]R v Turner (1975) 1 All ER 70.
[5] Stockdale, Michael, and Adam Jackson. ‘Expert Evidence in Criminal Proceedings.’ (2016) The Journal of Criminal Law. https://doi.org/10.1177/0022018316668448.
[6] Swetalika Das, ‘A Look into the Treatment of Expert Witness Evidence in English Law in the Light of the 21st Century.’ (2021) IPleaders https://blog.ipleaders.in/a-look-into-the-treatment-of-expert-witness-evidence-in-english-law-in-light-of-the-21st-century/.
[7] Martire, Kristy A, and Gary Edmond. ‘Rethinking Expert Opinion Evidence.’ (2017) Melbourne University Law Review 40:967. Accessed from https://law.unimelb.edu.au/__data/assets/pdf_file/0008/2494286/07-Martire-and-Edmond.pdf
[8] Stockdale (n5).
[9] Forensic Science on Trial, Seventh Report (2004–2005) HC 96-1.
[10] Law Commission Consultation Paper No. 190 (2009).
[11] Law Commission, ‘Expert evidence in criminal proceedings in England and Wales,’ (21 March 2011), Law Com No 325
[12] Stockdale (n5).
[13]Dainow, Joseph. ‘The Civil Law and the Common Law: Some Points of Comparison.’ (1966) The American Journal of Comparative Law 15:3 419–35. https://doi.org/10.2307/838275.
[14]R v Reed & Reed [2009] EWCA Crim. 2698.
[15] ibid.
[16]R v Turner (n4).
[17] Sharon Segal ‘When Expert Evidence Goes Wrong: Lessons from Case Laws.’ (2018) Experts in the Family Justice System (EFJS) Committee Accessed from https://www.judiciary.uk/wp-content/uploads/2021/05/Sharon-Segal-When-expert-evidence-goes-wrong.pdf.
[18] Stockdale (n5).
[19]R v Clarke Morabir [2013]EWCA Crim. 162.
[20] ibid.
[21] Fisher Retired BAJ, ‘A new challenge for expert witnesses relying on subjective information.’ (2017) Forensic Sci Res. 2(3):113-114.
[22]R v Hodges [2003] EWCA Crim. 290.
[23]R (Doughty) v Ely Magistrates’ Court [2008] EWHC 522.
[24] ibid.
[25] Tony Ward, ‘Explaining and trusting expert evidence: What is a ‘sufficiently reliable scientific basis’?’ (2020) The International Journal of Evidence & Proof, Accessed April 8, 2023. https://doi.org/10.1177/1365712720927622.
[26]R v T [2010] EWCA Crim 2439.
[27] GS Morrison ‘The Likelihood-Ratio Framework and Forensic Evidence in Court: A Response to R v T’ (2012) 16 International Journal of Evidence and Proof 1.
[28]R v Riat [2012] EWCA Crim 1509, [2013] 1 WLR 2592 [33].
[29] Tony (n25).
[30]Re NL (Appeal: Interim Care Order: Facts and Reasons) [2014] 1 FLR 1384.
[31] ibid.
[32] Sharon (n19).
[33] Tony Ward. ‘‘A new and more rigorous approach’ to expert evidence in England and Wales?’ (2015) The International Journal of Evidence & Proof). Accessed April 9, 2023. https://doi.org/10.1177/1365712715591471.
[34] I Freckleton, J Goodman, J Horan and B McKimmie Expert Evidence and Criminal Jury Trials (Oxford University Press New York, 2016) 1.09.
[35] Criminal Practice Directives, 2015 19A(6).
[36] Jacqueline Elton, ‘Expert Evidence, Juries and the Search for Truth: A Case Study Analysis.’ (DPhil Dissertation, De Montfort University 2019).
[37] Criminal Procedure Rules, 2020 No. 759 (L. 19).
[38] ibid.
[39] ibid, Rule 19(2).
[40]R v Reynolds, R v Rosser[2014] EWCA Crim 2205.
[41] Criminal Procedure Rules (n36) Rule 19.4 (a).
[42] Makanje GD, ‘The Admissibility of Expert Evidence in Criminal Proceedings in Malawi: A Call for Reliability Safeguards’ (2023) 67 Journal of African Law 117.
[43] Tony Ward, ‘Expert evidence and the Law Commission: implementation without legislation?’ (2018) accessed from https://hull-repository.worktribe.com/OutputFile/469916.
[44] ibid.
[45]Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579 (1993).
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