Outer House, Court of Session — Summary of Opinion by Judge Poole

Factual and Procedural Background

A pedestrian (the Deceased) lost his life after being struck by a bus. An action for damages was brought by the Deceased's executor-dative and bereaved family members (the Pursuers) against the bus operator (the Defender). That action settled. The Pursuers sought to recover, as judicial expenses, the fees paid to a number of skilled persons who produced reports prior to settlement.

It was agreed between the parties and accepted by the court that three skilled persons who prepared reports for the Pursuers should be certified for recovery of their fees: Expert A (a consultant road traffic investigator), Expert B (a consultant in emergency medicine), and Expert C (a consultant physician in geriatric, general and stroke medicine). The Defender opposed certification of a fourth expert, Expert D (a professor of psychology and applied neuroscience specialising in human visual perception). The opinion explains why the court declined to certify Expert D under the rules governing taxation of judicial expenses.

Representatives appearing in the proceedings were Attorney Thomson for the Pursuers and Attorney Murray for the Defender; the Pursuers' instructing firm is recorded as Company A and the Defender's firm as Company B in the source.

Legal Issues Presented

1. Whether Expert D was a "skilled person" within the meaning of rule 5.3(2)(a) of the Act of Sederunt (Taxation of Judicial Expenses Rules) 2019.
2. Whether, applying rule 5.3(2)(b) of the 2019 Rules, it was "reasonable and proportionate" (or "it is, or was, reasonable and proportionate") that Expert D should have been employed in this case — the central contested question in the application for certification.
3. How the factual circumstances at the time of instruction, and the existing evidence and expert involvement, informed the assessment of reasonableness and proportionality under rule 5.3(2)(b).

Arguments of the Parties

Pursuers' Arguments

• The Pursuers submitted that Expert D possessed relevant expertise in human visual perception, luminance and conspicuity, and was therefore a proper choice to address those aspects raised in the Defender's pleadings and adjustments.
• The Pursuers explained that they instructed Expert D in response to the Defender's pleadings (characterised by language such as "luminance contrast" and "not conspicuous") and after considering possible specialists; they selected Expert D as a reasonably priced option compared to other potential experts.
• The Pursuers relied on the proposition that Expert D's evidence would assist in assessing visibility and conspicuity issues relevant to liability for the collision.

Defender's Arguments

• The Defender accepted that Expert D is a skilled person but opposed certification on the ground that it was not reasonable and proportionate to instruct Expert D in the circumstances of this relatively straightforward road traffic accident.
• The Defender pointed to the substantial factual evidence already available to the court (CCTV from the bus, police collision investigation materials, photographic evidence and witness statements) and to the fact that the Pursuers had already instructed Expert A (the road traffic investigator) before instructing Expert D.
• The Defender indicated that its own evidence on conspicuity and related matters derived from a road traffic investigator (referred to in the source as Expert E), and argued that such material meant additional psychological/ neuroscience evidence was unnecessary and disproportionate.

Table of Precedents Cited

Precedent	Rule or Principle Cited For	Application by the Court
Philip v Scottish Ministers [2021] CSOH 52	That the court primarily considers the circumstances at the time of instruction when assessing reasonableness and proportionality under rule 5.3(2)(b).	The court relied on this principle to focus on the circumstances existing when Expert D was instructed, not on later events such as settlement.
Webster v MacLeod 2018 SAC (Civ) 16	Supports the approach that timing of instruction is the key focus for reasonableness/proportionality.	Used as an authority to reinforce that the court should consider the position at the time the expert was instructed.
Allison v Orr 2004 SC 453	That the later settlement of an action is not a factor to be taken into account when assessing whether an instruction was reasonable at the time it was made.	The court cited this to confirm settlement does not retroactively make an instruction reasonable.
Cameron v Swan [2021] CSIH 30	That expert evidence on general visibility/conspicuity may be unnecessary because such matters can be within a judge's fact-finding capability; and a statement about Expert D's eminence.	The court relied heavily on Cameron: parties agreed Expert D's expertise was not in question, and Cameron had found it wrong to rely on Expert D for general visibility/conspicuity as those matters were within judicial capability. That precedent weighed against certifying Expert D here.
Liddell v Middleton [1996] PIQR p36	Observation that parties increasingly enlist experts even when unnecessary, adding to litigation cost.	The court used the principle as contextual authority for caution about unnecessary expert instruction in straightforward personal injury/road traffic cases.
Kennedy v Cordia (Services) LLP [2016] UKSC 6 (2016 SC (UKSC) 59)	That determination of primary facts and breach of duty is for the judge, not an expert witness.	The court cited the principle to support the view that Expert D's evidence on liability-related perceptual issues was not necessary where a judge could reach conclusions using common sense and experience.
Taylor v Raspin (aka Raspin v Taylor) [2022] EWCA Civ 1613	Used in support of limits on the admissibility/utility of expert evidence.	The court treated it as part of the jurisprudence that expert evidence should be admitted only where it genuinely assists the court beyond judicial experience.
Stewart v Glaze [2009] EWHC 704	On the utility of expert road traffic witnesses in reconstructing accidents using circumstantial evidence.	The court noted that Expert A's work was of the type recognised in Stewart as assisting fact-finding; that made a further specialist on perception less justifiable here.

Court's Reasoning and Analysis

The court applied rule 5.3(2) of the 2019 Rules. The parties were agreed that Expert D satisfied rule 5.3(2)(a) (that he was a skilled person). The contested issue was rule 5.3(2)(b): whether it was reasonable and proportionate that Expert D should be employed in these proceedings. The court emphasised that the relevant inquiry focuses on the circumstances at the time Expert D was instructed.

The court identified four principal factors that led to refusal of certification for Expert D:

1. Subject matter of the action: This was a relatively straightforward road traffic accident. The court observed that there has been a trend to enlist experts where unnecessary, and that judges can, by applying common sense and experience, reach conclusions about whether a driver should have seen a pedestrian and avoided collision. Expert evidence will not be permitted where a judge can form a sound judgment without it. The court concluded these are issues a judge could decide in this case without specialised psychological or neuroscience evidence.
2. Nature of the evidence otherwise available: There was substantial material already available to assist the court on liability, including CCTV from the bus, police collision investigation materials with photographs and findings, and witness evidence including admissible hearsay of the driver's statements. In addition, the Pursuers had instructed Expert A (a former police officer and now consultant road traffic investigator). Expert A produced a detailed report (first consulted 20 January 2025, formal report 3 June 2025) including photographs of the scene, lighting, crossing points, bus damage and clothing. The court accepted that expert road traffic reconstruction can be important in some cases, and therefore certified Expert A; but that existing evidence meant a further skilled person on perception was disproportionate here.
3. Nature of the issues for determination: The central contested factual issues (whether the driver looked away, whether the driver should have kept a lookout, whether darkness, clothing, other lights or glare made the pedestrian difficult to see, and whether the pedestrian should have used a crossing) were not complex or beyond judicial experience. The Defender's pleadings had used technical language such as "luminance contrast" and "not conspicuous", which prompted the Pursuers to seek Expert D; however, the Inner House in Cameron had already held that general evidence from Expert D on visibility/conspicuity was within judicial capability and should not have been relied on. That authority pre-dated the instruction in this case and indicated such evidence was unlikely to be admissible or necessary.
4. Steps taken by the Pursuers before instructing Expert D: The court assessed whether the Pursuers had acted reasonably in deciding to instruct Expert D. The timeline indicated Expert A had been consulted on 20 January 2025 and produced a formal report on 3 June 2025. Expert D was initially retained on 30 April 2025. The Pursuers had explored other potential specialists (one quoted a very high fee) and chose Expert D partly on cost grounds. Crucially, when asked by the Defender on 19 June 2025, the Defender disclosed it relied on Expert E (a road traffic investigator) for evidence on conspicuity; Expert E's report was dated 6 March 2025 and therefore pre-existed the instruction of Expert D. The court considered that the Pursuers could and should have made further enquiries of the Defender about the basis for its averments and about the expertise of the person relied upon, before commissioning a full report from Expert D. The Pursuers proceeded to instruct a full report from Expert D on 26 June 2025 despite knowing the Defender relied on a road traffic investigator on those issues; the Pursuers did not see Expert E's report until 25 July 2025 (filed in accordance with the timetable). The court found it was not reasonable or proportionate to instruct Expert D for a full report in those circumstances.

Taking all factors together — the straightforward nature of the case, the substantial other evidence including Expert A's report, the character of the issues (which were within judicial capability), and the inadequate inquiry by the Pursuers before instructing Expert D — the court concluded that the condition in rule 5.3(2)(b) was not met in the specific circumstances of this case.

Holding and Implications

Application for certification of Expert D refused.

Direct effect: As a result of the refusal, the Pursuers cannot recover, as judicial expenses from the Defender, the fees and expenses associated with instructing Expert D (the professor of psychology and applied neuroscience). The court granted certification for the other three skilled persons whose reports were prepared for the Pursuers (Expert A, Expert B and Expert C), but not for Expert D.

Broader implications: The opinion does not announce any new principle of law; it applies existing rules and authorities (as cited) to the particular factual circumstances. The decision underscores established points: certification under the 2019 Rules requires not only that a person is skilled but that their instruction was reasonable and proportionate judged primarily at the time of instruction, and that judges should guard against unnecessary expert instruction in relatively straightforward factual disputes where judicial fact-finding is appropriate.

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Note on anonymization: Personal names and firm names in the original opinion have been replaced with consistent generic placeholders (for example, "Expert A"–"Expert E", "Attorney Thomson", "Attorney Murray", "Company A", "Company B", "Company C", and "Company D") to maintain confidentiality while preserving the substance of the court's reasoning as set out in the provided opinion.