The Criminal Justice System has long been criticized for its inability to prevent unreliable expert evidence from entering the courtroom. This situation justifies 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.
Expert Evidence Issues
Rather than imposing blanket exclusions, it is necessary to 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. The Law Commission reported in 2011 that 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.
A UK study by Ireland and Beaumont in 2015 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”. The Criminal Procedure Rules require that an expert witness be both competent and suitably qualified to provide an objective, unbiased opinion.
Likewise, the common law establishes that an expert must possess specialised skill, sufficient knowledge, and expertise acquired through study or experience. 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.
Ireland and Beaumont observe that the courts appear to have adopted a “good enough” approach to assessing expertise, rather than insisting upon strict compliance with the established standards. 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.
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This 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 is 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 key 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.
Police Expert Witness Concerns
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.
However, as noted in the infamous case, Hanif and Khan v UK, 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. According to the Morris Inquiry, 2004 police officers were unable to be “impartial participants in the prosecution process”.
This 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. 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.
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Therefore, improved regulation of officers is necessary, and it would be illogical to withdraw officers as expert witnesses entirely. 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.
New Categories of Evidence
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. Steyn LJ wrote that it would “be entirely wrong to deny the law of evidence the advantages to be gained from new techniques and advances in science”.
The courts have sought to find a balance: aware of the dangerous consequences of over expansion, as Stockwell and Gray 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”.
This seems the correct approach, however it can still be argued that lip reading seems equally as open to error. The approach adopted seems inconsistent, however it is done with good intention and a steer towards regulation. Thus, addressing the primary factor of the CJS operating to allow unreliable expert evidence into trials.
The issue of unreliable expert evidence is a significant one.
It affects the integrity of the trial process.