英语论文网

prosecution from giving opinion evidence as an expert in his field to support the prosecution’s case.

In R v. Chung Chen Hsin [23] (Chung), a police officer ballistics expert, who was possibly connected with the investigation, was called by the prosecution as witness to testify for them that the unusual weapon found in the defendant’s hand luggage was a “firearm”. The court has made some important points regarding the right of the prosecution authority to call its own officers as expert witnesses to offer opinion evidence. It is held that there is no requirement in a criminal proceeding where the expert witness ought to be independent of the prosecution authority, but a witness who is “competent and properly qualified” to provide his expertise would suffice. [24] Judge Stuart Moore also challenged the judgment in R v. Kai Tai Construction Engineering Company Ltd. [25] by claiming that “it was not a “material irregularity” for the prosecution to have called a properly qualified expert from the same department responsible for that prosecution,” and there must be “powerful reasons” to cast a doubt on the expert called by the prosecution in order to justify the refusal to allow the prosecution’s own officers as expert witnesses. [26] Moreover, even the expert witness is so closely connected to the case that he may be biased in favour of the prosecution, it is ultimately a matter remained for the jury to assess the weight to be attached to his testimony and the question of admissibility is irrelevant.

The rationale in Chung was reaffirmed in many recent cases, such as Tang Ping Choi & Another v. Secretary for Transport [27] , where the court held that an expert’s evidence was not inadmissible merely due to the fact that he or she was an employee of one of the parties to the case. With limited human resources in Hong Kong, the fact that many expert witnesses have been employed by the party calling them is nearly inevitable, especially for the technical matters that require highly specialized experts to offer their opinion evidence.

Despite the possible lack of independence of the expert witnesses employed by the prosecution, it has been made clear by the Hong Kong courts that the expert evidence would not be excluded merely on that basis. Even though the expert witness may have produced a biased opinion due to his or her vested interest in the outcome of the case, it is only relevant to the weight to be attached to that expert’s testimony rather than the admissibility of evidence.

Expert disagreement

With one of more expert witnesses giving opinion evidence at court, it is possible to have a clash of opinion between opposing experts. In fact, we may divide the discussion into two parts: one is the role the judge if this situation happens at the trial; while the other is the judge’s powers to limit the extent of expert disagreement before the trial.

First of all, if there are conflicting expert’s opinions during the trial, the judge will need to direct the jury correctly. It is held by the Court of Appeal in Plait [28] that the judge should not direct the jury in a way that it is a case of choosing between their opinion evidence. Rather, the jury should consider if there is a reasonable possibility that either the opinion of the prosecution or defence expert, when taken in conjunction with all the other evidence, is correct; then the jury should proceed on