The Criminal Justice System (CJS) has long been criticised for its inability to prevent unreliable expert evidence from entering the courtroom. At first glance, this may appear to justify the introduction of a stringent regime that excludes all evidence deemed ‘unreliable’. However, such an approach risks undermining the jury’s ability to reach informed decisions, by depriving it of the specialist assistance that expert witnesses are intended to provide. Rather than imposing blanket exclusions, we must consider whether a more effective solution is to address the root of the problem by establishing robust safeguards and regulatory mechanisms to ensure the reliability and quality of expert evidence, before it reaches the courtroom.
As reported by the Law Commission in 2011, expert evidence has been admitted “too readily” and “with insufficient scrutiny” with “a laissez-faire” approach; ultimately leading to severe risks of miscarriage of justice.[1] Indeed, Ireland and Beaumont’s 2015 UK study found that 20% of expert witnesses were not fully qualified in the field they offered comment on. In addition, 90% of experts were not currently practicing in their field or were retired, and “so lacked contemporary and current knowledge or experience”.[2]
However, it would be misguided to attribute these shortcomings solely to the framework established by the Criminal Procedure Rules 2020, the common law, or the relevant case law. The Criminal Procedure Rules require that an expert witness be both competent and suitably qualified to provide an objective, unbiased opinion.[3] Likewise, the common law establishes that an expert must possess specialised skill, sufficient knowledge, and expertise acquired through study or experience.[4] Collectively, these requirements set a demanding threshold which, if applied rigorously, should ensure that only credible, competent, and appropriately qualified experts are permitted to give evidence.
The more significant issue lies in the courts’ application of these principles. In practice, courts have at times been willing to recognise individuals as expert witnesses despite deficiencies in their qualifications or expertise. A witness who lacks the requisite qualifications should not be regarded as sufficiently qualified to offer expert opinion evidence. As Ireland and Beaumont observe, the courts appear to have adopted a “good enough” approach to assessing expertise, rather than insisting upon strict compliance with the established standards.[5] Given the court’s gatekeeping responsibility over the admissibility of evidence, a more rigorous approach is required to ensure that only genuinely qualified experts are permitted to testify. Such an approach would better protect the integrity of the trial process and uphold the right to a fair trial under Article 6 of the Human Rights Act 1998.
In addition, the expert witness regime has been further marred by the failure to ensure a formal verification process of an expert witness qualifications, with the courts only able to consider the information they are presented with. Once the court are satisfied that the expert is a person of knowledge within a specific field, applying the criteria set out within s30 (5), CJA 1988 and Criminal Procedure Rules 2020, there are minimal checks and vetting procedures enforced by the court to verify if the person is a genuine and real expert. Indeed, there is little to prevent a person from masquerading as an expert, through forgery of documentation or other means. As Jim Gamble, the former head of the Child Exploitation and Online Protection Command (CEOP) Centre commented, the expertise of such witnesses is something on which the court decides. However, whether or not they are witnesses of truth is a matter for us all.
This is troubling, as expert evidence carries a significant and pivotal role within the trial process. Whilst the jury are only expected to take the expert opinion into consideration, alongside all other evidence, when determining the facts and the outcome of the case, in reality, the authority of expert reports, can have a monumental effect on swaying the jury. Therefore, its source requires verification. This failure to address the possibility of misrepresentation by experts is seen in the prosecution of Jim Bates, 2008. An individual who falsely claimed to possess an electronic engineering degree and acted as an expert for the police in several serious investigations. Such events emphasise the need for reform, with a consequential benefit to the jury.
A possible solution to this, may lie in the introduction of a requirement for experts to be subject to background checks to verify their credentials. However, the assignment of this role to the courts poses issues. To expect court staff, to carry out this verification process would significantly impact the administration and efficiency of justice –adding to the judicial backlog following Covid-19 pandemic. There is a suggestion that the CPS could, at the very least, regulate and verify their use of experts, however the CPS claim they are not in a position to quality assure individuals or organisations who provide expert witness services to the CJS. Whilst this is disappointing, there does at least exist the UK Register of Expert Witnesses, 1988, containing a list of approximately 3000 verified expert witnesses. One feels this system should be advanced and implemented across the judicial system – requiring all experts to be registered before giving evidence to the court. Thus, aiding juries with reliable expert evidence.
Furthermore, the use of current and retired police officers as expert witnesses to prosecute drug related and rap related offences, owing to their detailed understanding of the complexities of these offences, poses difficulties. Indeed, it is required that an expert must be able to provide objective and unbiased evidence on the matters within their field of expertise; complying with their duty to the court.[6] However, as noted in the infamous case, Hanif and Khan v UK[7], reports suggest police officers suffer from an inherent sense of loyalty towards those in the force. There is a “culture of group loyalty and a tendency to assume guilt”. And so, the involvement of police raises issues regarding impartiality and whether the evidence can ever be relied on. Moreover, according to the Morris Inquiry, 2004 police officers were unable to be “impartial participants in the prosecution process”.[8] Which suggests CrimPR 19.2 (1) (a), can hardly be satisfied.
However, it is noted that we must not be too quick to categorise all police experts as impartial: applying the Rotten Apple Theory. To strike down all police experts, would be to deprive the court and jury of an experienced field of specialist officers, that have received extensive training in issues such as drug trafficking and firearms. Therefore, one would suggest improved regulation of officers, and would stop short of any illogical withdrawal of officers as expert witnesses.
However, whilst there is the need for regulation and the tackling of risk by the courts, progress has been made. The courts have maintained a wide approach when dealing with new categories of expert evidence that have emerged, treating the law as a living instrument. These new categories primarily owe their creation to developments in science. With the common law placing emphasis on a suitable expert possessing “a sufficiently reliable scientific basis for the expert evidence”: the law has had to adapt accordingly.[9] With Steyn LJ, writing it would “be entirely wrong to deny the law of evidence the advantages to be gained from new techniques and advances in science”.[10]
However, the courts have sought to find a balance: aware of the dangerous consequences of over expansion, as Stockwell[11] and Gray[12] exemplifies; where facial mapping was deemed inadmissible expert evidence due to its unreliability and absence of regulation. Indeed, in the latter case, the court suggested that “a national database or agreed formula for determining the occurrence of facial characteristics” was required, otherwise evidence could “only be viewed as a subjective opinion”.[13] This seems the correct approach, however one could still argue that lip reading seems equally as open to error. And so the approach adopted seems inconsistent, however with good intention and a steer towards regulation. Thus, addressing the primary factor of the CJS operating to allow unreliable expert evidence into trials.
In conclusion, the CJS has created ample opportunity for expert evidence that is unregulated and unreliable to enter the courtroom. However, rather than an archaic approach of the courts simply extending their powers to strike down all evidence with a hint of ambiguity and unreliability, a system of checks and regulations should be brought into the assessment of expert evidence, to improve the current crisis we face.
By Damir Kayani
[1] The Law Commission, (2011), “Expert evidence in Criminal Proceedings in England and Wales”, LAW COM No 325
[2] Ireland, Beaumont, (2015), “Admitting scientific expert evidence in the UK: reliability challenges and the need for revised criteria – proposing an Abridged Daubert”, Journal of Forensic Practice, Vol. 17 Issue: 1
[3] CrimPR 19.2 (1) (a)
[4] R v Silverlock [1894] 2 QB 766; R v Robb [1991] 93 Cr
[5] Ireland, Beaumont, (2015), “Admitting scientific expert evidence in the UK: reliability challenges and the need for revised criteria – proposing an Abridged Daubert”, Journal of Forensic Practice, Vol. 17 Issue: 1
[6] CrimPR 19.2 (1) (a)
[7] Hanif and Khan v UK (Applications nos. 52999/08 and 61779/08)
[8] Lord Bingham, R v Abdroikof [2007] UKHL 37
[9] R v Reed [2009] EWCA Crim 2698
[10] R v Clarke (RL) [1995] 2 Cr App R 425
[11] R v Stockwell (1993) 97 Cr App R 260
[12] R v Gray [2003] EWCA Crim 1001
[13] Ibid