Doughty v Ely Magistrates' Court

Expert evidence is admissible where the witness has sufficient knowledge, acquired through study or experience, to provide assistance on the specific issue before the court. The assessment must be focused on the subject matter of the proposed opinion and the information available to the court.

Recent use of a particular device, attendance at manufacturer courses, comparative superiority over another expert, disagreements in technical interpretation, and defects in an expert report may affect the weight of the evidence. They do not, without more, establish that the witness is incompetent to give expert evidence at all.

The claimant, a specialist in road traffic matters, sought judicial review of a ruling by Ely Magistrates' Court. The magistrates had excluded him from giving expert evidence for a defendant charged with speeding, holding that he lacked sufficient expertise in the operation and use of an LTI 20:20 speed detection device. The claimant argued that the magistrates had treated matters relevant to the weight of his evidence as matters going to competence.

The central issue was whether the magistrates were reasonably entitled to conclude, on the information before them, that the claimant was not competent to give expert evidence on the device.

1. The court granted the application for judicial review. The magistrates' ruling was unreasonable because the matters relied upon did not provide a proper basis for excluding the claimant as an expert witness altogether.

2. The governing principles were taken from R v Bonython [1984] 38 SASR 45. The court must determine whether the subject matter is one on which expert evidence is permissible and whether the witness has acquired, through study or experience, sufficient knowledge to make the opinion valuable in resolving the issues before the court. The inquiry must be focused on the particular issues and the information available in the case.

3. The claimant had substantial relevant qualifications and experience, including previous use of the LTI 20:20 and continuing work concerning speed detection devices. The fact that he had not operated that device since 1999, had not attended manufacturer courses, and did not have expertise equivalent to the prosecution expert did not reasonably demonstrate that his opinion could be of no value. The manufacturer’s courses were unavailable to defence experts, making reliance on non-attendance particularly inappropriate.

4. Disagreements about the meaning of an error message were matters for competing evidence and assessment of weight. Similarly, allegedly inadmissible material in an expert report could be excluded or excised without preventing the witness from giving evidence altogether. The quality of the report, the witness’s ultimate reliability, and whether he had exceeded the proper scope of expert evidence were not sufficient reasons for ruling him incompetent.

5. Mrs Justice Swift agreed with Lord Justice Richards. The judgment of the court was considered sufficient relief, and there was no order as to costs.

• Ely Magistrates' Court: ruled that the claimant was not an expert witness competent to give opinion evidence concerning the LTI 20:20 device.
• High Court (Administrative Court): granted judicial review and held that the magistrates' conclusion was unreasonable.